1. Booch G (1994) Object-Oriented Analysis Design with Application. The Bensamin/Cummings Publishing Co, Inc, p 15
2. Casey JS (1989) GoldWorks II for the SUN-3 or SUN386i. Gold Hills Computers Inc, Cambridge, MA
3. Chen, P. (1976) The entity relationship model – toward a unified view of data, ACM Trans Database Syst, Volume 1, Number 1, p9–36
4. CODASYL (1971) CODASYL Data Base task group report. Conferenc on data system languages. ACM, New York
5. Date C (1995) Introduction to database systems, 6th edn. Addison-Wesley Systems Programming Series, pp 669–685