diff --git a/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformComposition.class.st b/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformComposition.class.st
index 316698f..1e5ef5d 100644
--- a/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformComposition.class.st
+++ b/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformComposition.class.st
@@ -8,13 +8,28 @@ Class {
 
 { #category : 'transforming' }
 OntoUMLTransformComposition >> createComposition [
+
 	| composition |
 	composition := OPUMLAssociation new.
 	composition name: transformer name.
-	self createCompositionEndFor: composition withEndType: transformed general withOpposingEnd: transformed specific navigable: false.
-	self createCompositionEndFor: composition withEndType: transformed specific withOpposingEnd: transformed general navigable: true.
-	composition memberEnds addAll: composition ownedEnds.
-	^ composition.
+
+	composition memberEnds add: (self
+			 createCompositionEndFor: composition
+			 withEndType: transformed general
+			 withOpposingEnd: transformed specific
+			 navigable: false).
+	composition memberEnds add: (self
+			 createCompositionEndFor: composition
+			 withEndType: transformed specific
+			 withOpposingEnd: transformed general
+			 navigable: true).
+	self assert: composition memberEnds size = 2 description: [
+		'Generated association has only 1 end. '
+		, (transformer transformed generalizations size = 1
+				 ifTrue: [
+				 ' Might be caused by generalization set with only 1 generalization' ]
+				 ifFalse: [ '' ]) ].
+	^ composition
 ]
 
 { #category : 'transforming' }
diff --git a/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralization.class.st b/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralization.class.st
index 4c972d5..ef6e695 100644
--- a/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralization.class.st
+++ b/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralization.class.st
@@ -8,11 +8,14 @@ Class {
 
 { #category : 'transforming' }
 OntoUMLTransformGeneralization >> transform [
+
 	| generalization |
 	generalization := OPUMLGeneralization new.
-	generalization specific: (controller getTransfomedElementFrom: transformed specific).
-	generalization general: (controller getTransfomedElementFrom: transformed general).
-	self copyCommentsFrom: transformed to: generalization. 
+	generalization specific:
+		(controller getTransfomedElementFrom: transformed specific).
+	generalization general:
+		(controller getTransfomedElementFrom: transformed general).
+	self copyCommentsFrom: transformed to: generalization.
 	controller addElementToTransformedModel: generalization.
-	^ generalization.
+	^ generalization
 ]
diff --git a/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralizationSet.class.st b/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralizationSet.class.st
index 0098ead..5190a05 100644
--- a/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralizationSet.class.st
+++ b/src/OpenPonk-OntoUML-Transformations/OntoUMLTransformGeneralizationSet.class.st
@@ -206,19 +206,25 @@ OntoUMLTransformGeneralizationSet >> setGeneralProperties [
 
 { #category : 'private - transforming - composition' }
 OntoUMLTransformGeneralizationSet >> setName [
-	((transformer name ifNil: [ '' ]) endsWith: 'XOR') ifTrue: [ ^ self. ].
-	transformer name: (transformer transformed name ifNil: [ transformer general name ]) , ' - XOR'.
+
+	((transformer name ifNil: [ '' ]) endsWith: 'XOR') ifTrue: [ ^ self ].
+	transformer name:
+		(transformer transformed name ifNil: [ transformer general name ])
+		, ' - XOR'
 ]
 
 { #category : 'transforming' }
 OntoUMLTransformGeneralizationSet >> transform [
-	| selection |	
- 	transformer transformed isDisjoint ifTrue: [ ^ self transformDisjointGeneralization. ].
+
+	| selection |
+	transformer transformed isDisjoint ifTrue: [
+		^ self transformDisjointGeneralization ].
 	selection := self getSelection.
-	(selection = 'Gen') ifTrue: [ ^ self transformAsGeneralization. ].
-	(selection = 'GenAndComp') ifTrue: [ ^ self transformAsGeneralizationAndComposition. ].
-	(selection = 'Comp') ifTrue: [ ^ self transformAsComposition. ].
-	^ nil.
+	selection = 'Gen' ifTrue: [ ^ self transformAsGeneralization ].
+	selection = 'GenAndComp' ifTrue: [
+		^ self transformAsGeneralizationAndComposition ].
+	selection = 'Comp' ifTrue: [ ^ self transformAsComposition ].
+	^ nil
 ]
 
 { #category : 'transforming' }