S. Jacobs, and R. Holten. Proceedings of the Conference on Organizational Computing Systems (COOCS), August 13-16, 1995, page 96--105. Milpitas, CA, ACM, ACM, (1995)
C. Rolland, and C. Salinesi. Conceptual Modeling: Foundations and Applications, volume 5600 of Lecture Notes in Computer Science, page 398-416. Springer, (2009)