M. Zaki, S. Parthasarathy, M. Ogihara, und W. Li. Proceedings of the 3rd international conference on Knowledge Discovery
and Data mining (KDD'97), Seite 283--286. AAAI Press, (August 1997)
J. Bezdek, W. Li, Y. Attikiouzel, und M. Windham. Soft Computing - A Fusion of Foundations, Methodologies and Applications1 (4):
166--179(Dezember 1997)