M. Keeler. Proceedings of the 18th International Conference on Conceptual Structures (ICCS 2010), volume 6208 of Lecture Notes in Computer Science, page 108-124. Springer, (2010)
M. Keeler, and A. Majumdar. Proceedings of the 16th International Conference on Conceptual Structures (ICCS 2008), volume 5113 of Lecture Notes in Computer Science, page 88-103. Springer, (2008)