A. de Moor. Proceedings of the 12th International Conference on Conceptual Structures (ICCS 2004), Volume 3127 von Lecture Notes in Computer Science, Seite 261-274. Springer, (2004)
M. Northover, A. Boake, und D. Kourie. Proceedings of the 14th International Conference on Conceptual Structures (ICCS 2006), Volume 4068 von Lecture Notes in Computer Science, Seite 360-373. Springer, (2006)