Proceedings of the 9th International Conference on Entity-Relationship Approach (ER'90), 8-10 October, 1990, Lausanne, Switzerland.

Hannu Kangassalo Proceedings of the 9th International Conference on Entity-Relationship Approach (ER'90), 8-10 October, 1990, Lausanne, Switzerland. ER Institute 1990 db/conf/er/er90.html