Conceptual Modeling ER'99 18th International Conference on Conceptual Modeling Paris, France, November 15-18, 1999 Proceedings - Akoka, Jacky; Akoka, Jacky; Bouzeghoub, Mokrane; Bouzeghoub, Mokrane; Comyn-Wattiau, Isabelle; Comyn-Wattiau, Isabelle; Metais, Elisabeth; Metais, Elisabeth (Springer Berlin Heidelberg : Imprint: Springer, 1999)