A. Broder, S. Glassman, M. Manasse, and G. Zweig. Selected papers from the sixth international conference on World
Wide Web, page 1157--1166. Essex, UK, Elsevier Science Publishers Ltd., (1997)
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)