M. Grahl, A. Hotho, and G. Stumme. Workshop Proceedings of Lernen -- Wissensentdeckung -- Adaptivität (LWA 2007), page 50-54. Martin-Luther-Universität Halle-Wittenberg, (September 2007)
B. Krause, A. Hotho, and G. Stumme. Advances in Information Retrieval, 30th European Conference on IR Research, ECIR 2008, volume 4956 of LNAI, page 101-113. Heidelberg, Springer, (2008)
M. Grahl, A. Hotho, and G. Stumme. 7th International Conference on Knowledge Management (I-KNOW '07), page 356-364. Graz, Austria, Know-Center, (September 2007)