H. Halpin, and H. Thompson. WWW '06: Proceedings of the 15th international conference on World Wide Web, page 679--686. New York, NY, USA, ACM Press, (2006)
D. Gruhl, D. Meredith, J. Pieper, A. Cozzi, and S. Dill. WWW '06: Proceedings of the 15th international conference on World Wide Web, page 183--192. New York, NY, USA, ACM Press, (2006)
X. Wu, L. Zhang, and Y. Yu. WWW '06: Proceedings of the 15th international conference on World Wide Web, page 417--426. New York, NY, USA, ACM Press, (2006)