C. Schmitz, A. Hotho, R. Jäschke, and G. Stumme. Data Science and Classification (Proc. IFCS 2006 Conference), page 261-270. Berlin/Heidelberg, Springer, (July 2006)Ljubljana.
R. Agrawal, T. Imielinski, and A. Swami. SIGMOD '93: Proceedings of the 1993 ACM SIGMOD international conference on Management of data, page 207--216. New York, NY, USA, ACM Press, (1993)