B. Krause, R. Jäschke, A. Hotho, and G. Stumme. HT '08: Proceedings of the Nineteenth ACM Conference on Hypertext and Hypermedia, page 157--166. New York, NY, USA, ACM, (2008)
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)