F. Baader. Proceedings of the International Symposium on Knowledge Retrieval, Use, and Storage for Efficiency, KRUSE 95, page 168--178. Santa Cruz, USA, (1995)
K. Becker, G. Stumme, R. Wille, U. Wille, and M. Zickwolff. Knowledge Engineering and Knowledge Management. Methods, Models, and Tools., volume 1937 of LNAI, page 352-365. Heidelberg, Springer, (2000)