A. Broder, M. Najork, and J. Wiener. WWW '03: Proceedings of the 12th international conference on World
Wide Web, page 679--689. New York, NY, USA, ACM, (2003)
A. Broder, and A. Karlin. SODA '90: Proceedings of the first annual ACM-SIAM symposium on Discrete
algorithms, page 43--53. Philadelphia, PA, USA, Society for Industrial and Applied Mathematics, (1990)