PPMN_ — Line 1006 refers to a class "EntityTypeRelationship" which is not defined.

Line 1006 is the only reference to EntityTypeRelationship. This raises the question around the two class names "EntityRelationshipType" and "EntityTypeRelationship" mentioned in the same section 8.1.4. Combined with the fact that fig. 3 shows a derived attribute "part" for EntityTypes, i.e. an aggregation of Composition RelationshipKind amongst associations of an EntityType instance suggest we are missing some constructs in the diagram. At the very least, I believe a clearer text explanation is warranted.