ACM - affordances
Adair Dingle
David Umphress
Russ Moul
ACM SIGCSE Bulletin
Normalization in OODB design
models, languages, design, Oxford University Press, Oxford, 1997
A relational model of data for large shared data banks
ODMG-93, Morgan Kaufmann Publishers Inc
About the third rule of class normalization
Creating new classes of object forms