P. Heymann, D. Ramage, and H. Garcia-Molina. Proceedings of the 31st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 531--538. New York, NY, USA, ACM, (2008)
R. Jäschke, B. Krause, A. Hotho, and G. Stumme. Proceedings of the Second International Conference on Weblogs and Social Media (ICWSM 2008), page 192--193. Menlo Park, CA, USA, AAAI Press, (2008)
A. Hotho, R. Jäschke, C. Schmitz, and G. Stumme. Proceedings of the First International Conference on Semantic and Digital Media Technologies, page 56--70. Berlin, Heidelberg, Springer-Verlag, (2006)