(ref.doc)OOPSLA86

Object-oriented programming systems, languages and applications '86
Proceedings

pp 483-495
The Management of Changing Types in an Object-Oriented Database
by Andrea H. Skarra and Stanley B. Zdonik

Objects of the type and its subtypes are dependent on the type
definition for their implementation and interpretation.
Objects such as application programs that use objects of the type and
its subtypes are dependent on the interface.