Y. Ahn, S. Han, H. Kwak, S. Moon, and H. Jeong. Proceedings of the 16th International Conference on World Wide Web, page 835--844. New York, NY, USA, ACM, (2007)
E. Zheleva, and L. Getoor. WWW '09: Proceedings of the 18th International Conference on World Wide Web, page 531--540. New York, NY, USA, ACM, (April 2009)