Frithjof Dau Marie-Laure Mugnier Gerd Stumme Conceptual Structures: Common Semantics for Sharing Knowledge, 13th International Conference on Conceptual Structures, ICCS 2005, Kassel, Germany, July 17-22, 2005, Proceedings 3596 3-540-27783-8 2005 ICCS Lecture Notes in Computer Science Springer db/conf/iccs/iccs2005.html