diff --git a/.vscode/settings.json b/.vscode/settings.json
index 90f4a622..6c125ef7 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -94,6 +94,7 @@
     "Quantor",
     "razdel",
     "reagraph",
+    "redef",
     "Reindex",
     "rsconcept",
     "rsedit",
diff --git a/rsconcept/backend/apps/rsform/graph.py b/rsconcept/backend/apps/rsform/graph.py
index 528220c0..2a8289e0 100644
--- a/rsconcept/backend/apps/rsform/graph.py
+++ b/rsconcept/backend/apps/rsform/graph.py
@@ -1,42 +1,54 @@
 ''' Utility: Graph implementation. '''
-from typing import Iterable, Optional, cast
+import copy
+from typing import Generic, Iterable, Optional, TypeVar
 
 
-class Graph:
+ItemType = TypeVar("ItemType")
+
+
+class Graph(Generic[ItemType]):
     ''' Directed graph. '''
-    def __init__(self, graph: Optional[dict[str, list[str]]]=None):
+    def __init__(self, graph: Optional[dict[ItemType, list[ItemType]]]=None):
         if graph is None:
-            self._graph = cast(dict[str, list[str]], {})
+            self.outputs: dict[ItemType, list[ItemType]] = {}
+            self.inputs: dict[ItemType, list[ItemType]] = {}
         else:
-            self._graph = graph
+            self.outputs = graph
+            self.inputs: dict[ItemType, list[ItemType]] = {id : [] for id in graph.keys()} #type: ignore[no-redef]
+            for parent in graph.keys():
+                for child in graph[parent]:
+                    self.inputs[child].append(parent)
 
-    def contains(self, node_id: str) -> bool:
+    def contains(self, node_id: ItemType) -> bool:
         ''' Check if node is in graph. '''
-        return node_id in self._graph
+        return node_id in self.outputs
 
-    def has_edge(self, id_from: str, id_to: str) -> bool:
+    def has_edge(self, src: ItemType, dest: ItemType) -> bool:
         ''' Check if edge is in graph. '''
-        return self.contains(id_from) and id_to in self._graph[id_from]
+        return self.contains(src) and dest in self.outputs[src]
 
-    def add_node(self, node_id: str):
+    def add_node(self, node_id: ItemType):
         ''' Add node to graph. '''
         if not self.contains(node_id):
-            self._graph[node_id] = []
+            self.outputs[node_id] = []
+            self.inputs[node_id] = []
 
-    def add_edge(self, id_from: str, id_to: str):
+    def add_edge(self, src: ItemType, dest: ItemType):
         ''' Add edge to graph. '''
-        self.add_node(id_from)
-        self.add_node(id_to)
-        if id_to not in self._graph[id_from]:
-            self._graph[id_from].append(id_to)
+        self.add_node(src)
+        self.add_node(dest)
+        if dest not in self.outputs[src]:
+            self.outputs[src].append(dest)
+        if src not in self.inputs[dest]:
+            self.inputs[dest].append(src)
 
-    def expand_outputs(self, origin: Iterable[str]) -> list[str]:
+    def expand_inputs(self, origin: Iterable[ItemType]) -> list[ItemType]:
         ''' Expand origin nodes forward through graph edges. '''
-        result: list[str] = []
-        marked: set[str] = set(origin)
+        result: list[ItemType] = []
+        marked: set[ItemType] = set(origin)
         for node_id in origin:
             if self.contains(node_id):
-                for child_id in self._graph[node_id]:
+                for child_id in self.inputs[node_id]:
                     if child_id not in marked and child_id not in result:
                         result.append(child_id)
         position: int = 0
@@ -45,19 +57,51 @@ class Graph:
             position += 1
             if node_id not in marked:
                 marked.add(node_id)
-                for child_id in self._graph[node_id]:
+                for child_id in self.inputs[node_id]:
                     if child_id not in marked and child_id not in result:
                         result.append(child_id)
         return result
 
-    def topological_order(self) -> list[str]:
-        ''' Return nodes in topological order. '''
-        result: list[str] = []
-        marked: set[str] = set()
-        for node_id in self._graph.keys():
+    def expand_outputs(self, origin: Iterable[ItemType]) -> list[ItemType]:
+        ''' Expand origin nodes forward through graph edges. '''
+        result: list[ItemType] = []
+        marked: set[ItemType] = set(origin)
+        for node_id in origin:
+            if self.contains(node_id):
+                for child_id in self.outputs[node_id]:
+                    if child_id not in marked and child_id not in result:
+                        result.append(child_id)
+        position: int = 0
+        while position < len(result):
+            node_id = result[position]
+            position += 1
+            if node_id not in marked:
+                marked.add(node_id)
+                for child_id in self.outputs[node_id]:
+                    if child_id not in marked and child_id not in result:
+                        result.append(child_id)
+        return result
+
+    def transitive_closure(self) -> dict[ItemType, list[ItemType]]:
+        ''' Generate transitive closure - list of reachable nodes for each node. '''
+        result = copy.deepcopy(self.outputs)
+        order = self.topological_order()
+        order.reverse()
+        for node_id in order:
+            if len(self.inputs[node_id]) == 0:
+                continue
+            for parent in self.inputs[node_id]:
+                result[parent] = result[parent] + [id for id in result[node_id] if not id in result[parent]]
+        return result
+
+    def topological_order(self) -> list[ItemType]:
+        ''' Return nodes in SOME topological order. '''
+        result: list[ItemType] = []
+        marked: set[ItemType] = set()
+        for node_id in self.outputs.keys():
             if node_id in marked:
                 continue
-            to_visit: list[str] = [node_id]
+            to_visit: list[ItemType] = [node_id]
             while len(to_visit) > 0:
                 node = to_visit[-1]
                 if node in marked:
@@ -66,10 +110,33 @@ class Graph:
                     to_visit.remove(node)
                 else:
                     marked.add(node)
-                    if len(self._graph[node]) <= 0:
+                    if len(self.outputs[node]) <= 0:
                         continue
-                    for child_id in self._graph[node]:
+                    for child_id in self.outputs[node]:
                         if child_id not in marked:
                             to_visit.append(child_id)
         result.reverse()
         return result
+
+    def sort_stable(self, target: list[ItemType]) -> list[ItemType]:
+        ''' Returns target stable sorted in topological order based on minimal modifications. '''
+        if len(target) <= 1:
+            return target
+        reachable = self.transitive_closure()
+        test_set: set[ItemType] = set()
+        result: list[ItemType] = []
+        for node_id in reversed(target):
+            need_move = node_id in test_set
+            test_set = test_set.union(reachable[node_id])
+            if not need_move:
+                result.append(node_id)
+                continue
+            for (index, parent) in enumerate(result):
+                if node_id in reachable[parent]:
+                    if parent in reachable[node_id]:
+                        result.append(node_id)
+                    else:
+                        result.insert(index, node_id)
+                    break
+        result.reverse()
+        return result
diff --git a/rsconcept/backend/apps/rsform/models/Constituenta.py b/rsconcept/backend/apps/rsform/models/Constituenta.py
index d6de7760..a94b673f 100644
--- a/rsconcept/backend/apps/rsform/models/Constituenta.py
+++ b/rsconcept/backend/apps/rsform/models/Constituenta.py
@@ -2,13 +2,12 @@
 import re
 
 from django.db.models import (
-    CASCADE, ForeignKey, Model, PositiveIntegerField,
+    CASCADE, ForeignKey, Model, PositiveIntegerField, TextChoices,
     TextField, CharField, JSONField
 )
 from django.core.validators import MinValueValidator
 from django.urls import reverse
 
-from .api_RSLanguage import CstType
 from ..utils import apply_pattern
 
 
@@ -20,8 +19,20 @@ def _empty_forms():
     return []
 
 
+class CstType(TextChoices):
+    ''' Type of constituenta. '''
+    BASE = 'basic'
+    CONSTANT = 'constant'
+    STRUCTURED = 'structure'
+    AXIOM = 'axiom'
+    TERM = 'term'
+    FUNCTION = 'function'
+    PREDICATE = 'predicate'
+    THEOREM = 'theorem'
+
+
 class Constituenta(Model):
-    ''' Constituenta is the base unit for every conceptual schema '''
+    ''' Constituenta is the base unit for every conceptual schema. '''
     schema: ForeignKey = ForeignKey(
         verbose_name='Концептуальная схема',
         to='rsform.LibraryItem',
diff --git a/rsconcept/backend/apps/rsform/models/api_RSForm.py b/rsconcept/backend/apps/rsform/models/api_RSForm.py
index 51771e2c..31ff352a 100644
--- a/rsconcept/backend/apps/rsform/models/api_RSForm.py
+++ b/rsconcept/backend/apps/rsform/models/api_RSForm.py
@@ -1,13 +1,29 @@
 ''' Models: RSForm API. '''
 from copy import deepcopy
-from typing import Iterable, Optional, Union, cast
+from typing import Optional, Union, cast
 
 from django.db import transaction
 from django.db.models import QuerySet
 from django.core.exceptions import ValidationError
 
-from cctext import Resolver, Entity, extract_entities, split_grams, TermForm
-from .api_RSLanguage import get_type_prefix, generate_structure, guess_type
+from cctext import (
+    Resolver,
+    Entity,
+    extract_entities,
+    split_grams,
+    TermForm
+)
+from .api_RSLanguage import (
+    extract_globals,
+    get_type_prefix,
+    generate_structure,
+    guess_type,
+    infer_template,
+    is_base_set,
+    is_functional,
+    is_simple_expression,
+    split_template
+)
 from .LibraryItem import LibraryItem, LibraryItemType
 from .Constituenta import CstType, Constituenta
 from .Version import Version
@@ -49,18 +65,22 @@ class RSForm:
             result.context[cst.alias] = entity
         return result
 
+    def semantic(self) -> 'SemanticInfo':
+        ''' Access semantic information on constituents. '''
+        return SemanticInfo(self)
+
     @transaction.atomic
-    def on_term_change(self, changed: Iterable[str]):
+    def on_term_change(self, changed: list[int]):
         ''' Trigger cascade resolutions when term changes. '''
-        graph_terms = self._term_graph()
+        graph_terms = self._graph_term()
         expansion = graph_terms.expand_outputs(changed)
-        expanded_change = list(changed) + expansion
+        expanded_change = changed + expansion
         resolver = self.resolver()
         if len(expansion) > 0:
-            for alias in graph_terms.topological_order():
-                if alias not in expansion:
+            for cst_id in graph_terms.topological_order():
+                if cst_id not in expansion:
                     continue
-                cst = self.constituents().get(alias=alias)
+                cst = self.constituents().get(id=cst_id)
                 resolved = resolver.resolve(cst.term_raw)
                 if resolved == cst.term_resolved:
                     continue
@@ -68,12 +88,12 @@ class RSForm:
                 cst.save()
                 resolver.context[cst.alias] = Entity(cst.alias, resolved)
 
-        graph_defs = self._definition_graph()
+        graph_defs = self._graph_text()
         update_defs = set(expansion + graph_defs.expand_outputs(expanded_change)).union(changed)
         if len(update_defs) == 0:
             return
-        for alias in update_defs:
-            cst = self.constituents().get(alias=alias)
+        for cst_id in update_defs:
+            cst = self.constituents().get(id=cst_id)
             resolved = resolver.resolve(cst.definition_raw)
             if resolved == cst.definition_resolved:
                 continue
@@ -199,7 +219,7 @@ class RSForm:
         if cst.definition_raw != '':
             cst.definition_resolved = resolver.resolve(cst.definition_raw)
         cst.save()
-        self.on_term_change([cst.alias])
+        self.on_term_change([cst.id])
         cst.refresh_from_db()
         return cst
 
@@ -220,7 +240,12 @@ class RSForm:
             substitution.term_resolved = original.term_resolved
             substitution.save()
         original.delete()
-        self.on_term_change([substitution.alias])
+        self.on_term_change([substitution.id])
+
+    def restore_order(self):
+        ''' Restore order based on types and term graph. '''
+        manager = _OrderManager(self)
+        manager.restore_order()
 
     def reset_aliases(self):
         ''' Recreate all aliases based on constituents order. '''
@@ -251,10 +276,10 @@ class RSForm:
     @transaction.atomic
     def resolve_all_text(self):
         ''' Trigger reference resolution for all texts. '''
-        graph_terms = self._term_graph()
+        graph_terms = self._graph_term()
         resolver = Resolver({})
-        for alias in graph_terms.topological_order():
-            cst = self.constituents().get(alias=alias)
+        for cst_id in graph_terms.topological_order():
+            cst = self.constituents().get(id=cst_id)
             resolved = resolver.resolve(cst.term_raw)
             resolver.context[cst.alias] = Entity(cst.alias, resolved)
             if resolved != cst.term_resolved:
@@ -352,30 +377,241 @@ class RSForm:
         else:
             return self.insert_new(data['alias'], data['cst_type'])
 
-    def _term_graph(self) -> Graph:
-        result = Graph()
+    def _graph_formal(self) -> Graph[int]:
+        ''' Graph based on formal definitions. '''
+        result: Graph[int] = Graph()
         cst_list = \
             self.constituents() \
-                .only('order', 'alias', 'term_raw') \
+                .only('id', 'order', 'alias', 'definition_formal') \
                 .order_by('order')
         for cst in cst_list:
-            result.add_node(cst.alias)
+            result.add_node(cst.id)
         for cst in cst_list:
-            for alias in extract_entities(cst.term_raw):
-                if result.contains(alias):
-                    result.add_edge(id_from=alias, id_to=cst.alias)
+            for alias in extract_globals(cst.definition_formal):
+                try:
+                    child = cst_list.get(alias=alias)
+                    result.add_edge(src=child.id, dest=cst.id)
+                except Constituenta.DoesNotExist:
+                    pass
         return result
 
-    def _definition_graph(self) -> Graph:
-        result = Graph()
+    def _graph_term(self) -> Graph[int]:
+        ''' Graph based on term texts. '''
+        result: Graph[int] = Graph()
         cst_list = \
             self.constituents() \
-                .only('order', 'alias', 'definition_raw') \
+                .only('id', 'order', 'alias', 'term_raw') \
                 .order_by('order')
         for cst in cst_list:
-            result.add_node(cst.alias)
+            result.add_node(cst.id)
+        for cst in cst_list:
+            for alias in extract_entities(cst.term_raw):
+                try:
+                    child = cst_list.get(alias=alias)
+                    result.add_edge(src=child.id, dest=cst.id)
+                except Constituenta.DoesNotExist:
+                    pass
+        return result
+
+    def _graph_text(self) -> Graph[int]:
+        ''' Graph based on definition texts. '''
+        result: Graph[int] = Graph()
+        cst_list = \
+            self.constituents() \
+                .only('id', 'order', 'alias', 'definition_raw') \
+                .order_by('order')
+        for cst in cst_list:
+            result.add_node(cst.id)
         for cst in cst_list:
             for alias in extract_entities(cst.definition_raw):
-                if result.contains(alias):
-                    result.add_edge(id_from=alias, id_to=cst.alias)
+                try:
+                    child = cst_list.get(alias=alias)
+                    result.add_edge(src=child.id, dest=cst.id)
+                except Constituenta.DoesNotExist:
+                    pass
         return result
+
+
+class SemanticInfo:
+    ''' Semantic information derived from constituents. '''
+    def __init__(self, schema: RSForm):
+        self._graph = schema._graph_formal()
+        self._items = list(
+            schema.constituents() \
+                .only('id', 'alias', 'cst_type', 'definition_formal') \
+                .order_by('order')
+        )
+        self._cst_by_alias = { cst.alias : cst for cst in self._items }
+        self._cst_by_ID = { cst.id : cst for cst in self._items }
+        self.info = {
+            cst.id: {
+                'is_simple' : False, \
+                'is_template' : False, \
+                'parent' : cst.id, \
+                'children' : [] 
+            }
+            for cst in self._items
+        }
+        self._calculate_attributes()
+
+    def __getitem__(self, key: int) -> dict:
+        return self.info[key]
+
+    def is_simple_expression(self, target: int) -> bool:
+        ''' Access "is_simple" attribute. '''
+        return cast(bool, self.info[target]['is_simple'])
+
+    def is_template(self, target: int) -> bool:
+        ''' Access "is_template" attribute. '''
+        return cast(bool, self.info[target]['is_template'])
+
+    def parent(self, target: int) -> int:
+        ''' Access "parent" attribute. '''
+        return cast(int, self.info[target]['parent'])
+
+    def children(self, target: int) -> list[int]:
+        ''' Access "children" attribute. '''
+        return cast(list[int], self.info[target]['children'])
+
+    def _calculate_attributes(self):
+        for cst_id in self._graph.topological_order():
+            cst = self._cst_by_ID[cst_id]
+            self.info[cst_id]['is_template'] = infer_template(cst.definition_formal)
+            self.info[cst_id]['is_simple'] = self._infer_simple_expression(cst)
+            if not self.info[cst_id]['is_simple'] or cst.cst_type == CstType.STRUCTURED:
+                continue
+            parent = self._infer_parent(cst)
+            self.info[cst_id]['parent'] = parent
+            if parent != cst_id:
+                self.info[parent]['children'].append(cst_id)
+
+    def _infer_simple_expression(self, target: Constituenta) -> bool:
+        if target.cst_type == CstType.STRUCTURED or is_base_set(target.cst_type):
+            return False
+
+        dependencies = self._graph.inputs[target.id]
+        has_complex_dependency = any(
+            self.is_template(cst_id) and \
+                not self.is_simple_expression(cst_id) for cst_id in dependencies
+        )
+        if has_complex_dependency:
+            return False
+
+        if is_functional(target.cst_type):
+            return is_simple_expression(split_template(target.definition_formal)['body'])
+        else:
+            return is_simple_expression(target.definition_formal)
+
+    def _infer_parent(self, target: Constituenta) -> int:
+        sources = self._extract_sources(target)
+        if len(sources) != 1:
+            return target.id
+        return next(iter(sources))
+
+    def _extract_sources(self, target: Constituenta) -> set[int]:
+        sources: set[int] = set()
+        if not is_functional(target.cst_type):
+            for parent_id in self._graph.inputs[target.id]:
+                parent_info = self[parent_id]
+                if not parent_info['is_template'] or not parent_info['is_simple']:
+                    sources.add(parent_info['parent'])
+            return sources
+
+        expression = split_template(target.definition_formal)
+        body_dependencies = extract_globals(expression['body'])
+        for alias in body_dependencies:
+            parent = self._cst_by_alias.get(alias)
+            if not parent:
+                continue
+
+            parent_info = self[parent.id]
+            if not parent_info['is_template'] or not parent_info['is_simple']:
+                sources.add(parent_info['parent'])
+
+        if self._need_check_head(sources, expression['head']):
+            head_dependencies = extract_globals(expression['head'])
+            for alias in head_dependencies:
+                parent = self._cst_by_alias.get(alias)
+                if not parent:
+                    continue
+
+                parent_info = self[parent.id]
+                if not is_base_set(parent.cst_type) and \
+                    (not parent_info['is_template'] or not parent_info['is_simple']):
+                    sources.add(parent_info['parent'])
+        return sources
+
+    def _need_check_head(self, sources: set[int], head: str)-> bool:
+        if len(sources) == 0:
+            return True
+        elif len(sources) != 1:
+            return False
+        else:
+            base = self._cst_by_ID[next(iter(sources))]
+            return not is_functional(base.cst_type) or \
+                split_template(base.definition_formal)['head'] != head
+
+
+class _OrderManager:
+    ''' Ordering helper class '''
+    def __init__(self, schema: RSForm):
+        self._semantic = schema.semantic()
+        self._graph = schema._graph_formal()
+        self._items = list(
+            schema.constituents() \
+                .only('id', 'order', 'alias', 'cst_type', 'definition_formal') \
+                .order_by('order')
+        )
+        self._cst_by_ID = { cst.id : cst for cst in self._items }
+
+    def restore_order(self) -> None:
+        ''' Implement order restoration process. '''
+        if len(self._items) <= 1:
+            return
+        self._fix_kernel()
+        self._fix_topological()
+        self._fix_semantic_children()
+        self._save_order()
+
+    def _fix_topological(self) -> None:
+        sorted_ids = self._graph.sort_stable([cst.id for cst in self._items])
+        sorted_items = [next(cst for cst in self._items if cst.id == id) for id in sorted_ids]
+        self._items = sorted_items
+
+    def _fix_kernel(self) -> None:
+        result = [cst for cst in self._items if cst.cst_type == CstType.BASE]
+        result = result + [cst for cst in self._items if cst.cst_type == CstType.CONSTANT]
+        kernel = [
+            cst.id for cst in self._items if \
+                cst.cst_type in [CstType.STRUCTURED, CstType.AXIOM] or \
+                    self._cst_by_ID[self._semantic.parent(cst.id)].cst_type == CstType.STRUCTURED
+        ]
+        kernel = kernel + self._graph.expand_inputs(kernel)
+        result = result + [cst for cst in self._items if result.count(cst) == 0 and cst.id in kernel]
+        result = result + [cst for cst in self._items if result.count(cst) == 0]
+        self._items = result
+
+    def _fix_semantic_children(self) -> None:
+        result: list[Constituenta] = []
+        marked: set[Constituenta] = set()
+        for cst in self._items:
+            if cst in marked:
+                continue
+            result.append(cst)
+            children = self._semantic[cst.id]['children']
+            if len(children) == 0:
+                continue
+            for child in self._items:
+                if child.id in children:
+                    marked.add(child)
+                    result.append(child)
+        self._items = result
+
+
+    @transaction.atomic
+    def _save_order(self) -> None:
+        order = 1
+        for cst in self._items:
+            cst.order = order
+            cst.save()
+            order += 1
diff --git a/rsconcept/backend/apps/rsform/models/api_RSLanguage.py b/rsconcept/backend/apps/rsform/models/api_RSLanguage.py
index 42829571..c4733ada 100644
--- a/rsconcept/backend/apps/rsform/models/api_RSLanguage.py
+++ b/rsconcept/backend/apps/rsform/models/api_RSLanguage.py
@@ -1,13 +1,18 @@
 ''' Models: Definitions and utility function for RSLanguage. '''
 import json
-from typing import Tuple, cast
+import re
+from typing import Set, Tuple, cast
 from enum import IntEnum , unique
 
-from django.db.models import TextChoices
-
 import pyconcept
 
 from .. import messages as msg
+from .Constituenta import CstType
+
+
+_RE_GLOBALS = r'[XCSADFPT]\d+' # cspell:disable-line
+_RE_TEMPLATE = r'R\d+'
+_RE_COMPLEX_SYMBOLS = r'[∀∃×ℬ;|:]'
 
 
 @unique
@@ -22,38 +27,51 @@ class TokenType(IntEnum):
     REDUCE = 299
 
 
-class CstType(TextChoices):
-    ''' Type of constituenta '''
-    BASE = 'basic'
-    CONSTANT = 'constant'
-    STRUCTURED = 'structure'
-    AXIOM = 'axiom'
-    TERM = 'term'
-    FUNCTION = 'function'
-    PREDICATE = 'predicate'
-    THEOREM = 'theorem'
-
-
 def get_type_prefix(cst_type: CstType) -> str:
     ''' Get alias prefix. '''
-    if cst_type == CstType.BASE:
-        return 'X'
-    if cst_type == CstType.CONSTANT:
-        return 'C'
-    if cst_type == CstType.STRUCTURED:
-        return 'S'
-    if cst_type == CstType.AXIOM:
-        return 'A'
-    if cst_type == CstType.TERM:
-        return 'D'
-    if cst_type == CstType.FUNCTION:
-        return 'F'
-    if cst_type == CstType.PREDICATE:
-        return 'P'
-    if cst_type == CstType.THEOREM:
-        return 'T'
+    match cst_type:
+        case CstType.BASE: return 'X'
+        case CstType.CONSTANT: return 'C'
+        case CstType.STRUCTURED: return 'S'
+        case CstType.AXIOM: return 'A'
+        case CstType.TERM: return 'D'
+        case CstType.FUNCTION:  return 'F'
+        case CstType.PREDICATE: return 'P'
+        case CstType.THEOREM: return 'T'
     return 'X'
 
+
+def is_basic_concept(cst_type: CstType) -> bool:
+    ''' Evaluate if CstType is basic concept.'''
+    return cst_type in [
+        CstType.BASE,
+        CstType.CONSTANT,
+        CstType.STRUCTURED,
+        CstType.AXIOM
+    ]
+
+
+def is_base_set(cst_type: CstType) -> bool:
+    ''' Evaluate if CstType is base set or constant set.'''
+    return cst_type in [
+        CstType.BASE,
+        CstType.CONSTANT
+    ]
+
+
+def is_functional(cst_type: CstType) -> bool:
+    ''' Evaluate if CstType is function.'''
+    return cst_type in [
+        CstType.FUNCTION,
+        CstType.PREDICATE
+    ]
+
+
+def extract_globals(expression: str) -> Set[str]:
+    ''' Extract all global aliases from expression. '''
+    return set(re.findall(_RE_GLOBALS, expression))
+
+
 def guess_type(alias: str) -> CstType:
     ''' Get CstType for alias. '''
     prefix = alias[0]
@@ -62,6 +80,7 @@ def guess_type(alias: str) -> CstType:
             return cast(CstType, value)
     return CstType.BASE
 
+
 def _get_structure_prefix(alias: str, expression: str, parse: dict) -> Tuple[str, str]:
     ''' Generate prefix and alias for structure generation. '''
     args = parse['args']
@@ -71,6 +90,43 @@ def _get_structure_prefix(alias: str, expression: str, parse: dict) -> Tuple[str
     newAlias = alias + '[' + ','.join([arg['alias'] for arg in args]) + ']'
     return (newAlias, prefix)
 
+
+def infer_template(expression: str) -> bool:
+    ''' Checks if given expression is a template. '''
+    return bool(re.search(_RE_TEMPLATE, expression))
+
+
+def is_simple_expression(expression: str) -> bool:
+    ''' Checks if given expression is "simple". '''
+    return not bool(re.search(_RE_COMPLEX_SYMBOLS, expression))
+
+
+def split_template(expression: str):
+    ''' Splits a string containing a template definition into its head and body parts. '''
+    start = 0
+    for index, char in enumerate(expression):
+        start = index
+        if char == '[':
+            break
+    if start < len(expression):
+        counter = 0
+        for end in range(start + 1, len(expression)):
+            if expression[end] == '[':
+                counter += 1
+            elif expression[end] == ']':
+                if counter != 0:
+                    counter -= 1
+                else:
+                    return {
+                        'head': expression[start + 1:end].strip(),
+                        'body': expression[end + 1:].strip()
+                    }
+    return {
+        'head': '',
+        'body': expression
+    }
+
+
 def generate_structure(alias: str, expression: str, parse: dict) -> list:
     ''' Generate list of expressions for target structure. '''
     ast = json.loads(pyconcept.parse_expression(parse['typification']))['ast']
diff --git a/rsconcept/backend/apps/rsform/serializers/data_access.py b/rsconcept/backend/apps/rsform/serializers/data_access.py
index 8c6714d7..aeaacf1c 100644
--- a/rsconcept/backend/apps/rsform/serializers/data_access.py
+++ b/rsconcept/backend/apps/rsform/serializers/data_access.py
@@ -89,7 +89,7 @@ class ConstituentaSerializer(serializers.ModelSerializer):
             term_changed = data['term_resolved'] != instance.term_resolved
         result: Constituenta = super().update(instance, data)
         if term_changed:
-            schema.on_term_change([result.alias])
+            schema.on_term_change([result.id])
             result.refresh_from_db()
         schema.item.save()
         return result
diff --git a/rsconcept/backend/apps/rsform/tests/__init__.py b/rsconcept/backend/apps/rsform/tests/__init__.py
index ecc597f6..134a34ae 100644
--- a/rsconcept/backend/apps/rsform/tests/__init__.py
+++ b/rsconcept/backend/apps/rsform/tests/__init__.py
@@ -1,7 +1,7 @@
 ''' Tests. '''
 from .t_imports import *
 from .s_views import *
-from .t_models import *
+from .s_models.t_RSForm import *
 from .t_serializers import *
 from .t_graph import *
 from .t_utils import *
diff --git a/rsconcept/backend/apps/rsform/tests/s_models/__init__.py b/rsconcept/backend/apps/rsform/tests/s_models/__init__.py
new file mode 100644
index 00000000..4ba5390a
--- /dev/null
+++ b/rsconcept/backend/apps/rsform/tests/s_models/__init__.py
@@ -0,0 +1,4 @@
+''' Tests for REST API. '''
+from .t_Constituenta import *
+from .t_LibraryItem import *
+from .t_RSForm import *
diff --git a/rsconcept/backend/apps/rsform/tests/s_models/t_Constituenta.py b/rsconcept/backend/apps/rsform/tests/s_models/t_Constituenta.py
new file mode 100644
index 00000000..4897d2ff
--- /dev/null
+++ b/rsconcept/backend/apps/rsform/tests/s_models/t_Constituenta.py
@@ -0,0 +1,68 @@
+''' Testing models: Constituenta. '''
+from django.test import TestCase
+from django.db.utils import IntegrityError
+from django.forms import ValidationError
+
+from apps.rsform.models import (
+    Constituenta, CstType,
+    LibraryItem, LibraryItemType
+)
+
+
+class TestConstituenta(TestCase):
+    ''' Testing Constituenta model. '''
+    def setUp(self):
+        self.schema1 = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test1')
+        self.schema2 = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test2')
+
+
+    def test_str(self):
+        testStr = 'X1'
+        cst = Constituenta.objects.create(alias=testStr, schema=self.schema1, order=1, convention='Test')
+        self.assertEqual(str(cst), testStr)
+
+
+    def test_url(self):
+        testStr = 'X1'
+        cst = Constituenta.objects.create(alias=testStr, schema=self.schema1, order=1, convention='Test')
+        self.assertEqual(cst.get_absolute_url(), f'/api/constituents/{cst.id}')
+
+
+    def test_order_not_null(self):
+        with self.assertRaises(IntegrityError):
+            Constituenta.objects.create(alias='X1', schema=self.schema1)
+
+
+    def test_order_positive_integer(self):
+        with self.assertRaises(IntegrityError):
+            Constituenta.objects.create(alias='X1', schema=self.schema1, order=-1)
+
+
+    def test_order_min_value(self):
+        with self.assertRaises(ValidationError):
+            cst = Constituenta.objects.create(alias='X1', schema=self.schema1, order=0)
+            cst.full_clean()
+
+
+    def test_schema_not_null(self):
+        with self.assertRaises(IntegrityError):
+            Constituenta.objects.create(alias='X1', order=1)
+
+
+    def test_create_default(self):
+        cst = Constituenta.objects.create(
+            alias='X1',
+            schema=self.schema1,
+            order=1
+        )
+        self.assertEqual(cst.schema, self.schema1)
+        self.assertEqual(cst.order, 1)
+        self.assertEqual(cst.alias, 'X1')
+        self.assertEqual(cst.cst_type, CstType.BASE)
+        self.assertEqual(cst.convention, '')
+        self.assertEqual(cst.definition_formal, '')
+        self.assertEqual(cst.term_raw, '')
+        self.assertEqual(cst.term_resolved, '')
+        self.assertEqual(cst.term_forms, [])
+        self.assertEqual(cst.definition_resolved, '')
+        self.assertEqual(cst.definition_raw, '')
diff --git a/rsconcept/backend/apps/rsform/tests/s_models/t_LibraryItem.py b/rsconcept/backend/apps/rsform/tests/s_models/t_LibraryItem.py
new file mode 100644
index 00000000..565d6dea
--- /dev/null
+++ b/rsconcept/backend/apps/rsform/tests/s_models/t_LibraryItem.py
@@ -0,0 +1,100 @@
+''' Testing models: LibraryItem. '''
+from django.test import TestCase
+
+from apps.rsform.models import (
+    LibraryItem, LibraryItemType, Subscription,
+    User
+)
+
+
+class TestLibraryItem(TestCase):
+    ''' Testing LibraryItem model. '''
+    def setUp(self):
+        self.user1 = User.objects.create(username='User1')
+        self.user2 = User.objects.create(username='User2')
+        self.assertNotEqual(self.user1, self.user2)
+
+
+    def test_str(self):
+        testStr = 'Test123'
+        item = LibraryItem.objects.create(
+            item_type=LibraryItemType.RSFORM,
+            title=testStr,
+            owner=self.user1,
+            alias='КС1'
+        )
+        self.assertEqual(str(item), testStr)
+
+
+    def test_url(self):
+        testStr = 'Test123'
+        item = LibraryItem.objects.create(
+            item_type=LibraryItemType.RSFORM,
+            title=testStr,
+            owner=self.user1,
+            alias='КС1'
+        )
+        self.assertEqual(item.get_absolute_url(), f'/api/library/{item.id}')
+
+
+    def test_create_default(self):
+        item = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test')
+        self.assertIsNone(item.owner)
+        self.assertEqual(item.title, 'Test')
+        self.assertEqual(item.alias, '')
+        self.assertEqual(item.comment, '')
+        self.assertEqual(item.is_common, False)
+        self.assertEqual(item.is_canonical, False)
+
+
+    def test_create(self):
+        item = LibraryItem.objects.create(
+            item_type=LibraryItemType.RSFORM,
+            title='Test',
+            owner=self.user1,
+            alias='KS1',
+            comment='Test comment',
+            is_common=True,
+            is_canonical=True
+        )
+        self.assertEqual(item.owner, self.user1)
+        self.assertEqual(item.title, 'Test')
+        self.assertEqual(item.alias, 'KS1')
+        self.assertEqual(item.comment, 'Test comment')
+        self.assertEqual(item.is_common, True)
+        self.assertEqual(item.is_canonical, True)
+        self.assertTrue(Subscription.objects.filter(user=item.owner, item=item).exists())
+
+
+    def test_subscribe(self):
+        item = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test')
+        self.assertEqual(len(item.subscribers()), 0)
+
+        self.assertTrue(Subscription.subscribe(self.user1, item))
+        self.assertEqual(len(item.subscribers()), 1)
+        self.assertTrue(self.user1 in item.subscribers())
+
+        self.assertFalse(Subscription.subscribe(self.user1, item))
+        self.assertEqual(len(item.subscribers()), 1)
+
+        self.assertTrue(Subscription.subscribe(self.user2, item))
+        self.assertEqual(len(item.subscribers()), 2)
+        self.assertTrue(self.user1 in item.subscribers())
+        self.assertTrue(self.user2 in item.subscribers())
+
+        self.user1.delete()
+        self.assertEqual(len(item.subscribers()), 1)
+
+
+    def test_unsubscribe(self):
+        item = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test')
+        self.assertFalse(Subscription.unsubscribe(self.user1, item))
+        Subscription.subscribe(self.user1, item)
+        Subscription.subscribe(self.user2, item)
+        self.assertEqual(len(item.subscribers()), 2)
+
+        self.assertTrue(Subscription.unsubscribe(self.user1, item))
+        self.assertEqual(len(item.subscribers()), 1)
+        self.assertTrue(self.user2 in item.subscribers())
+
+        self.assertFalse(Subscription.unsubscribe(self.user1, item))
diff --git a/rsconcept/backend/apps/rsform/tests/t_models.py b/rsconcept/backend/apps/rsform/tests/s_models/t_RSForm.py
similarity index 64%
rename from rsconcept/backend/apps/rsform/tests/t_models.py
rename to rsconcept/backend/apps/rsform/tests/s_models/t_RSForm.py
index d3344f2a..83eb71cf 100644
--- a/rsconcept/backend/apps/rsform/tests/t_models.py
+++ b/rsconcept/backend/apps/rsform/tests/s_models/t_RSForm.py
@@ -1,167 +1,13 @@
-''' Testing models '''
-import json
+''' Testing models: api_RSForm. '''
 from django.test import TestCase
-from django.db.utils import IntegrityError
 from django.forms import ValidationError
 
 from apps.rsform.models import (
     RSForm, Constituenta, CstType,
-    User,
-    LibraryItem, LibraryItemType, Subscription
+    User
 )
 
 
-class TestConstituenta(TestCase):
-    ''' Testing Constituenta model. '''
-    def setUp(self):
-        self.schema1 = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test1')
-        self.schema2 = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test2')
-
-    def test_str(self):
-        testStr = 'X1'
-        cst = Constituenta.objects.create(alias=testStr, schema=self.schema1, order=1, convention='Test')
-        self.assertEqual(str(cst), testStr)
-
-
-    def test_url(self):
-        testStr = 'X1'
-        cst = Constituenta.objects.create(alias=testStr, schema=self.schema1, order=1, convention='Test')
-        self.assertEqual(cst.get_absolute_url(), f'/api/constituents/{cst.id}')
-
-
-    def test_order_not_null(self):
-        with self.assertRaises(IntegrityError):
-            Constituenta.objects.create(alias='X1', schema=self.schema1)
-
-
-    def test_order_positive_integer(self):
-        with self.assertRaises(IntegrityError):
-            Constituenta.objects.create(alias='X1', schema=self.schema1, order=-1)
-
-
-    def test_order_min_value(self):
-        with self.assertRaises(ValidationError):
-            cst = Constituenta.objects.create(alias='X1', schema=self.schema1, order=0)
-            cst.full_clean()
-
-
-    def test_schema_not_null(self):
-        with self.assertRaises(IntegrityError):
-            Constituenta.objects.create(alias='X1', order=1)
-
-
-    def test_create_default(self):
-        cst = Constituenta.objects.create(
-            alias='X1',
-            schema=self.schema1,
-            order=1
-        )
-        self.assertEqual(cst.schema, self.schema1)
-        self.assertEqual(cst.order, 1)
-        self.assertEqual(cst.alias, 'X1')
-        self.assertEqual(cst.cst_type, CstType.BASE)
-        self.assertEqual(cst.convention, '')
-        self.assertEqual(cst.definition_formal, '')
-        self.assertEqual(cst.term_raw, '')
-        self.assertEqual(cst.term_resolved, '')
-        self.assertEqual(cst.term_forms, [])
-        self.assertEqual(cst.definition_resolved, '')
-        self.assertEqual(cst.definition_raw, '')
-
-
-class TestLibraryItem(TestCase):
-    ''' Testing LibraryItem model. '''
-    def setUp(self):
-        self.user1 = User.objects.create(username='User1')
-        self.user2 = User.objects.create(username='User2')
-        self.assertNotEqual(self.user1, self.user2)
-
-
-    def test_str(self):
-        testStr = 'Test123'
-        item = LibraryItem.objects.create(
-            item_type=LibraryItemType.RSFORM,
-            title=testStr,
-            owner=self.user1,
-            alias='КС1'
-        )
-        self.assertEqual(str(item), testStr)
-
-
-    def test_url(self):
-        testStr = 'Test123'
-        item = LibraryItem.objects.create(
-            item_type=LibraryItemType.RSFORM,
-            title=testStr,
-            owner=self.user1,
-            alias='КС1'
-        )
-        self.assertEqual(item.get_absolute_url(), f'/api/library/{item.id}')
-
-
-    def test_create_default(self):
-        item = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test')
-        self.assertIsNone(item.owner)
-        self.assertEqual(item.title, 'Test')
-        self.assertEqual(item.alias, '')
-        self.assertEqual(item.comment, '')
-        self.assertEqual(item.is_common, False)
-        self.assertEqual(item.is_canonical, False)
-
-
-    def test_create(self):
-        item = LibraryItem.objects.create(
-            item_type=LibraryItemType.RSFORM,
-            title='Test',
-            owner=self.user1,
-            alias='KS1',
-            comment='Test comment',
-            is_common=True,
-            is_canonical=True
-        )
-        self.assertEqual(item.owner, self.user1)
-        self.assertEqual(item.title, 'Test')
-        self.assertEqual(item.alias, 'KS1')
-        self.assertEqual(item.comment, 'Test comment')
-        self.assertEqual(item.is_common, True)
-        self.assertEqual(item.is_canonical, True)
-        self.assertTrue(Subscription.objects.filter(user=item.owner, item=item).exists())
-
-
-    def test_subscribe(self):
-        item = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test')
-        self.assertEqual(len(item.subscribers()), 0)
-
-        self.assertTrue(Subscription.subscribe(self.user1, item))
-        self.assertEqual(len(item.subscribers()), 1)
-        self.assertTrue(self.user1 in item.subscribers())
-
-        self.assertFalse(Subscription.subscribe(self.user1, item))
-        self.assertEqual(len(item.subscribers()), 1)
-
-        self.assertTrue(Subscription.subscribe(self.user2, item))
-        self.assertEqual(len(item.subscribers()), 2)
-        self.assertTrue(self.user1 in item.subscribers())
-        self.assertTrue(self.user2 in item.subscribers())
-
-        self.user1.delete()
-        self.assertEqual(len(item.subscribers()), 1)
-
-
-    def test_unsubscribe(self):
-        item = LibraryItem.objects.create(item_type=LibraryItemType.RSFORM, title='Test')
-        self.assertFalse(Subscription.unsubscribe(self.user1, item))
-        Subscription.subscribe(self.user1, item)
-        Subscription.subscribe(self.user2, item)
-        self.assertEqual(len(item.subscribers()), 2)
-
-        self.assertTrue(Subscription.unsubscribe(self.user1, item))
-        self.assertEqual(len(item.subscribers()), 1)
-        self.assertTrue(self.user2 in item.subscribers())
-
-        self.assertFalse(Subscription.unsubscribe(self.user1, item))
-
-
 class TestRSForm(TestCase):
     ''' Testing RSForm wrapper. '''
     def setUp(self):
@@ -377,6 +223,69 @@ class TestRSForm(TestCase):
         self.assertEqual(x2.order, 1)
 
 
+    def test_restore_order(self):
+        d2 = self.schema.insert_new(
+            alias='D2',
+            definition_formal=r'D{ξ∈S1 | 1=1}',
+        )
+        d1 = self.schema.insert_new(
+            alias='D1',
+            definition_formal=r'Pr1(S1)\X1',
+        )
+        x1 = self.schema.insert_new('X1')
+        x2 = self.schema.insert_new('X2')
+        s1 = self.schema.insert_new(
+            alias='S1',
+            definition_formal='ℬ(X1×X1)'
+        )
+        c1 = self.schema.insert_new('C1')
+        s2 = self.schema.insert_new(
+            alias='S2',
+            definition_formal='ℬ(X2×D1)'
+        )
+        a1 = self.schema.insert_new(
+            alias='A1',
+            definition_formal=r'D3=∅',
+        )
+        d3 = self.schema.insert_new(
+            alias='D3',
+            definition_formal=r'Pr2(S2)',
+        )
+        f1 = self.schema.insert_new(
+            alias='F1',
+            definition_formal=r'[α∈ℬ(X1)] D{σ∈S1 | α⊆pr1(σ)}',
+        )
+        d4 = self.schema.insert_new(
+            alias='D4',
+            definition_formal=r'Pr2(D3)',
+        )
+        
+        self.schema.restore_order()
+        x1.refresh_from_db()
+        x2.refresh_from_db()
+        c1.refresh_from_db()
+        s1.refresh_from_db()
+        s2.refresh_from_db()
+        d1.refresh_from_db()
+        d2.refresh_from_db()
+        d3.refresh_from_db()
+        d4.refresh_from_db()
+        f1.refresh_from_db()
+        a1.refresh_from_db()
+
+        self.assertEqual(x1.order, 1)
+        self.assertEqual(x2.order, 2)
+        self.assertEqual(c1.order, 3)
+        self.assertEqual(s1.order, 4)
+        self.assertEqual(d1.order, 5)
+        self.assertEqual(s2.order, 6)
+        self.assertEqual(d3.order, 7)
+        self.assertEqual(a1.order, 8)
+        self.assertEqual(d4.order, 9)
+        self.assertEqual(d2.order, 10)
+        self.assertEqual(f1.order, 11)
+
+
     def test_reset_aliases(self):
         x1 = self.schema.insert_new(
             alias='X11',
@@ -437,7 +346,7 @@ class TestRSForm(TestCase):
         x1.term_resolved='слон'
         x1.save()
 
-        self.schema.on_term_change([x1.alias])
+        self.schema.on_term_change([x1.id])
         x1.refresh_from_db()
         x2.refresh_from_db()
         x3.refresh_from_db()
diff --git a/rsconcept/backend/apps/rsform/tests/s_views/t_library.py b/rsconcept/backend/apps/rsform/tests/s_views/t_library.py
index afc54252..d2c4f6e2 100644
--- a/rsconcept/backend/apps/rsform/tests/s_views/t_library.py
+++ b/rsconcept/backend/apps/rsform/tests/s_views/t_library.py
@@ -4,7 +4,7 @@ from rest_framework import status
 from apps.users.models import User
 from apps.rsform.models import LibraryItem, LibraryItemType, Subscription, LibraryTemplate, RSForm
 
-from ..utils import response_contains
+from ..testing_utils import response_contains
 
 from .EndpointTester import decl_endpoint, EndpointTester
 
diff --git a/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py b/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py
index 0c5ec99b..338b9142 100644
--- a/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py
+++ b/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py
@@ -13,7 +13,7 @@ from apps.rsform.models import (
 )
 
 from cctext import ReferenceType
-from ..utils import response_contains
+from ..testing_utils import response_contains
 
 from .EndpointTester import decl_endpoint, EndpointTester
 
diff --git a/rsconcept/backend/apps/rsform/tests/t_graph.py b/rsconcept/backend/apps/rsform/tests/t_graph.py
index 1d2e884e..314e6dac 100644
--- a/rsconcept/backend/apps/rsform/tests/t_graph.py
+++ b/rsconcept/backend/apps/rsform/tests/t_graph.py
@@ -9,56 +9,107 @@ class TestGraph(unittest.TestCase):
     
     def test_construction(self):
         graph = Graph()
-        self.assertFalse(graph.contains('X1'))
+        self.assertFalse(graph.contains(1))
 
-        graph.add_node('X1')
-        self.assertTrue(graph.contains('X1'))
+        graph.add_node(1)
+        self.assertTrue(graph.contains(1))
 
-        graph.add_edge('X2', 'X3')
-        self.assertTrue(graph.contains('X2'))
-        self.assertTrue(graph.contains('X3'))
-        self.assertTrue(graph.has_edge('X2', 'X3'))
-        self.assertFalse(graph.has_edge('X3', 'X2'))
+        graph.add_edge(2, 3)
+        self.assertTrue(graph.contains(2))
+        self.assertTrue(graph.contains(3))
+        self.assertTrue(graph.has_edge(2, 3))
+        self.assertFalse(graph.has_edge(3, 2))
 
-        graph = Graph({'X1': ['X3', 'X4'], 'X2': ['X1'], 'X3': [], 'X4': [], 'X5': []})
-        self.assertTrue(graph.contains('X1'))
-        self.assertTrue(graph.contains('X5'))
-        self.assertTrue(graph.has_edge('X1', 'X3'))
-        self.assertTrue(graph.has_edge('X2', 'X1'))
+        graph = Graph({1: [3, 4], 2: [1], 3: [], 4: [], 5: []})
+        self.assertTrue(graph.contains(1))
+        self.assertTrue(graph.contains(5))
+        self.assertTrue(graph.has_edge(1, 3))
+        self.assertTrue(graph.has_edge(2, 1))
 
 
     def test_expand_outputs(self):
         graph = Graph({
-            'X1': ['X2'],
-            'X2': ['X3', 'X5'],
-            'X3': [],
-            'X5': ['X6'],
-            'X6': ['X1'],
-            'X7': []
+            1: [2],
+            2: [3, 5],
+            3: [],
+            5: [6],
+            6: [1],
+            7: []
         })
         self.assertEqual(graph.expand_outputs([]), [])
-        self.assertEqual(graph.expand_outputs(['X3']), [])
-        self.assertEqual(graph.expand_outputs(['X7']), [])
-        self.assertEqual(graph.expand_outputs(['X2', 'X5']), ['X3', 'X6', 'X1'])
+        self.assertEqual(graph.expand_outputs([3]), [])
+        self.assertEqual(graph.expand_outputs([7]), [])
+        self.assertEqual(graph.expand_outputs([2, 5]), [3, 6, 1])
 
+    def test_expand_inputs(self):
+        graph = Graph({
+            1: [2],
+            2: [3, 5],
+            3: [],
+            5: [6],
+            6: [1],
+            7: []
+        })
+        self.assertEqual(graph.expand_inputs([]), [])
+        self.assertEqual(graph.expand_inputs([1]), [6, 5, 2])
+        self.assertEqual(graph.expand_inputs([7]), [])
+        self.assertEqual(graph.expand_inputs([3]), [2, 1, 6, 5])
+        self.assertEqual(graph.expand_inputs([2, 5]), [1, 6])
+
+
+    def test_transitive_closure(self):
+        graph = Graph({
+            1: [2],
+            2: [3, 5],
+            3: [],
+            5: [6],
+            6: [],
+            7: [6]
+        })
+        self.assertEqual(graph.transitive_closure(), {
+            1: [2, 3, 5, 6],
+            2: [3, 5, 6],
+            3: [],
+            5: [6],
+            6: [],
+            7: [6]
+        })
 
     def test_topological_order(self):
         self.assertEqual(Graph().topological_order(), [])
         graph = Graph({
-            'X1': [],
-            'X2': ['X1'],
-            'X3': [],
-            'X4': ['X3'],
-            'X5': ['X6'],
-            'X6': ['X1', 'X2']
+            1: [],
+            2: [1],
+            3: [],
+            4: [3],
+            5: [6],
+            6: [1, 2]
         })
-        self.assertEqual(graph.topological_order(), ['X5', 'X6', 'X4', 'X3', 'X2', 'X1'])
+        self.assertEqual(graph.topological_order(), [5, 6, 4, 3, 2, 1])
 
         graph = Graph({
-            'X1': ['X1'],
-            'X2': ['X4'],
-            'X3': ['X2'],
-            'X4': [],
-            'X5': ['X2'],
+            1: [1],
+            2: [4],
+            3: [2],
+            4: [],
+            5: [2],
         })
-        self.assertEqual(graph.topological_order(), ['X5', 'X3', 'X2', 'X4', 'X1'])
+        self.assertEqual(graph.topological_order(), [5, 3, 2, 4, 1])
+
+    def test_sort_stable(self):
+        graph = Graph({
+            1: [2],
+            2: [3, 5],
+            3: [],
+            5: [6],
+            6: [],
+            7: [6]
+        })
+        self.assertEqual(graph.sort_stable([]), [])
+        self.assertEqual(graph.sort_stable([1]), [1])
+        self.assertEqual(graph.sort_stable([1, 2]), [1, 2])
+        self.assertEqual(graph.sort_stable([7, 2, 1]), [7, 1, 2])
+        self.assertEqual(graph.sort_stable([2, 1, 7]), [1, 2, 7])
+        self.assertEqual(graph.sort_stable([1, 2, 7]), [1, 2, 7])
+        self.assertEqual(graph.sort_stable([2, 1, 3, 6, 7]), [1, 2, 3, 7, 6])
+        self.assertEqual(graph.sort_stable([2, 1, 6, 7, 3]), [1, 2, 7, 6, 3])
diff --git a/rsconcept/backend/apps/rsform/tests/utils.py b/rsconcept/backend/apps/rsform/tests/testing_utils.py
similarity index 100%
rename from rsconcept/backend/apps/rsform/tests/utils.py
rename to rsconcept/backend/apps/rsform/tests/testing_utils.py
diff --git a/rsconcept/backend/apps/rsform/utils.py b/rsconcept/backend/apps/rsform/utils.py
index 893e8315..cdc8ce0c 100644
--- a/rsconcept/backend/apps/rsform/utils.py
+++ b/rsconcept/backend/apps/rsform/utils.py
@@ -9,6 +9,9 @@ from rest_framework.permissions import BasePermission, IsAuthenticated
 # Name for JSON inside Exteor files archive
 EXTEOR_INNER_FILENAME = 'document.json'
 
+# Old style reference pattern
+_REF_OLD_PATTERN = re.compile(r'@{([^0-9\-][^\}\|\{]*?)\|([^\}\|\{]*?)\|([^\}\|\{]*?)}')
+
 
 class ObjectOwnerOrAdmin(BasePermission):
     ''' Permission for object ownership restriction '''
@@ -47,6 +50,7 @@ class ItemOwnerOrAdmin(BasePermission):
             return False
         return request.user.is_staff # type: ignore
 
+
 def read_zipped_json(data, json_filename: str) -> dict:
     ''' Read JSON from zipped data '''
     with ZipFile(data, 'r') as archive:
@@ -63,6 +67,7 @@ def write_zipped_json(json_data: dict, json_filename: str) -> bytes:
         archive.writestr(json_filename, data=data)
     return content.getvalue()
 
+
 def apply_pattern(text: str, mapping: dict[str, str], pattern: re.Pattern[str]) -> str:
     ''' Apply mapping to matching in regular expression pattern subgroup 1 '''
     if text == '' or pattern == '':
@@ -79,7 +84,6 @@ def apply_pattern(text: str, mapping: dict[str, str], pattern: re.Pattern[str])
     output += text[pos_input : len(text)]
     return output
 
-_REF_OLD_PATTERN = re.compile(r'@{([^0-9\-][^\}\|\{]*?)\|([^\}\|\{]*?)\|([^\}\|\{]*?)}')
 
 def fix_old_references(text: str) -> str:
     ''' Fix reference format: @{X1|nomn|sing} -> {X1|nomn,sing} '''
@@ -94,6 +98,7 @@ def fix_old_references(text: str) -> str:
     output += text[pos_input : len(text)]
     return output
 
+
 def filename_for_schema(alias: str) -> str:
     ''' Generate filename for schema from alias. '''
     if alias == '' or not alias.isascii():
diff --git a/rsconcept/backend/apps/rsform/views/rsforms.py b/rsconcept/backend/apps/rsform/views/rsforms.py
index d2b047bb..858fadc8 100644
--- a/rsconcept/backend/apps/rsform/views/rsforms.py
+++ b/rsconcept/backend/apps/rsform/views/rsforms.py
@@ -246,7 +246,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
             status=c.HTTP_200_OK,
             data=s.RSFormParseSerializer(schema.item).data
         )
-    
+
     @extend_schema(
         summary='restore order based on types and term graph',
         tags=['RSForm'],
@@ -261,8 +261,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
     def restore_order(self, request: Request, pk):
         ''' Endpoint: Restore order based on types and term graph. '''
         schema = self._get_schema()
-        # TODO: implement reordering
-        # schema.reset_aliases()
+        schema.restore_order()
         return Response(
             status=c.HTTP_200_OK,
             data=s.RSFormParseSerializer(schema.item).data