C. Cattuto, D. Benz, A. Hotho, and G. Stumme. Proceedings of the 3rd Workshop on Ontology Learning and Population (OLP3), page 39--43. Patras, Greece, (July 2008)
C. Schmitz, A. Hotho, R. Jäschke, and G. Stumme. Data Science and Classification: Proc. of the 10th IFCS Conf., page 261--270. Berlin, Heidelberg, Springer, (2006)