S. Doerfel, D. Zoller, P. Singer, T. Niebler, A. Hotho, and M. Strohmaier. 23rd International World Wide Web Conference, WWW '14, Seoul, Republic of Korea, April 7-11, 2014, Companion Volume, page 251--252. New York, NY, USA, ACM, (2014)
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)