M. Keeler. Third International Conference on Conceptual Structures: Applications, Implementation and Theory, Proceedings Supplement, Dept. of Computer Science, University of California, Santa Cruz, page 94--107. (1995)
A. de Moor, M. Keeler, and G. Richmond. Proc. of the 10th International Conference on Conceptual Structures (ICCS 2002), Borovets, Bulgaria, July 15, page 235-249. (2002)
M. Keeler, L. Searle, and C. Kloesel. Proceedings of the Fifth International Conference on
Conceptual Structures, University of Washington, Seattle, August 3--8,
1997, page 505--520. (1997)