T. Pederson, C. Ardito, P. Bottoni, and M. Costabile. Advances in Conceptual Modeling -- Challenges and Opportunities: ER 2008 Workshops CMLSA, ECDM, FP-UML, M2AS, RIGiM, SeCoGIS, WISM, Barcelona, Spain, volume 5232 of Lecture Notes in Computer Science, (2008)