Hideko S. Kunii Sushil Jajodia Arne Sølvberg Conceptual Modeling - ER 2001, 20th International Conference on Conceptual Modeling, Yokohama, Japan, November 27-30, 2001, Proceedings ER Lecture Notes in Computer Science 2224 Springer 2001 3-540-42866-6 db/conf/er/er2001.html