1. http://www.internetworldstats.com/ http://www.internetlivestats.com/total-number-of-websites/#trend
2. On power-law relationships of the Internet topology;Faloutsos;ACM SIGCOMM Computer Communication Review,1999
3. Routing of multipoint connections;Waxman;IEEE Journal of Selected Areas in Communication,1988
4. Doar , M.B. 1996 A better model for generating test networks Proceedings of IEEE Global Internet London 86 93
5. Modeling Internet topology;Calvert;IEEE Communication Magazine,1997