N. Pahal, N. Chauhan, and A. Sharma. Wireless Communication and Sensor Networks, 2007. WCSN '07. Third International Conference on, page 121-124. (2007)
D. Kempe, J. Kleinberg, and &\#201;va Tardos. KDD '03: Proceedings of the ninth ACM SIGKDD international conference on Knowledge discovery and data mining, page 137--146. ACM Press, (2003)