Jacky Akoka Mokrane Bouzeghoub Isabelle Comyn-Wattiau Elisabeth Métais Conceptual Modeling - ER '99, 18th International Conference on Conceptual Modeling, Paris, France, November, 15-18, 1999, Proceedings ER Lecture Notes in Computer Science 1728 Springer 1999 3-540-66686-9 db/conf/er/er99.html