R. Iyer, D. Lewis, R. Schapire, Y. Singer, and A. Singhal. CIKM '00: Proceedings of the ninth international conference on Information and knowledge management, page 70--77. New York, NY, USA, ACM, (2000)
J. Newsome, E. Shi, D. Song, and A. Perrig. Information Processing in Sensor Networks, 2004. IPSN 2004. Third
International Symposium on, page 259--268. (2004)