Gerard Ellis Robert Levinson William Rich John F. Sowa Conceptual Structures: Applications, Implementation and Theory, Third International Conference on Conceptual Structures, ICCS '95, Santa Cruz, California, USA, August 14-18, 1995, Proceedings ICCS Lecture Notes in Computer Science 954 Springer 1995 3-540-60161-9 db/conf/iccs/iccs95.html