T. Tran, P. Haase, and R. Studer. Proceedings of the 17th International Conference on Conceptual Structures (ICCS 2009), volume 5662 of Lecture Notes in Computer Science, page 48-65. Springer, (2009)
M. Greaves. Proceedings of the 17th International Conference on Conceptual Structures (ICCS 2009), volume 5662 of Lecture Notes in Computer Science, page 1. Springer, (2009)