J. Yang, and J. Leskovec. Proceedings of the Sixth ACM International Conference on Web Search and Data Mining, page 587--596. New York, NY, USA, ACM, (2013)
C. Schmitz, A. Hotho, R. Jäschke, and G. Stumme. The Semantic Web: Research and Applications, volume 4011 of Lecture Notes in Computer Science, page 530--544. Berlin/Heidelberg, Springer, (June 2006)