R. Studer, G. Stumme, S. Handschuh, A. Hotho, and B. Motik. New Trends in Knowledge Processing - Data Mining, Semantic Web and Computational Science. Proc. 6th Sanken International Symposium, page 31-34. Osaka, Japan, (March 2003)March 10-11, 2003.
B. Berendt, A. Hotho, and G. Stumme. Proceedings of the First International Semantic Web Conference: The Semantic Web (ISWC 2002), volume 2342 of Lecture Notes in Computer Science (LNCS), page 264-278. Sardinia, Italy, Springer, (2002)
G. Stumme, and A. Maedche. IJCAI-2001 -- Proceedings of the 17th International Joint Conference on Artificial Intelligence, Seattle, USA, August, 1-6, 2001, page 225--234. San Francisco, Morgen Kaufmann, (2001)