G. Arumugam, M.Thangaraj, and R. Sasirekha. International Journal of Computer Science, Engineering and Information Technology (IJCSEIT), 1, page 09-19. ACM, (April 2011)
R. Kraft, and J. Zien. WWW '04: Proceedings of the 13th international conference on World Wide Web, page 666--674. New York, NY, USA, ACM Press, (2004)