Qing Li Stefano Spaccapietra Eric S. K. Yu Antoni Olivé Conceptual Modeling - ER 2008, 27th International Conference on Conceptual Modeling, Barcelona, Spain, October 20-24, 2008. Proceedings 5231 2008 978-3-540-87876-6 ER Lecture Notes in Computer Science Springer db/conf/er/er2008.html