S. Prediger, and G. Stumme. Proc. 6th Intl. Workshop Knowledge Representation Meets Databases (KRDB'99), CEUR Workshop Proc. 21, (1999)Also in: P. Lambrix et al (Eds.): Proc. Intl. Workshop on Description Logics (DL'99). CEUR Workshop Proc. 22, 1999 http://ceur-ws.org/Vol-21.
R. Jäschke, A. Hotho, C. Schmitz, B. Ganter, and G. Stumme. Proceedings of the 6th IEEE International Conference on Data Mining (ICDM 06), page 907-911. Hong Kong, IEEE Computer Society, (December 2006)