E. Oren, J. Breslin, и S. Decker. WWW '06: Proceedings of the 15th international conference on World Wide Web, стр. 1071--1072. New York, NY, USA, ACM Press, (2006)
W. Xi, B. Zhang, Z. Chen, Y. Lu, S. Yan, W. Ma, и E. Fox. WWW '04: Proceedings of the 13th international conference on World Wide Web, стр. 319--327. New York, NY, USA, ACM Press, (2004)