7Matzat U. Social networks and cooperation in electronic communities: A theoreticalempirical analysis of academic communication and Intemet discussion Groups: [Dissertation]. Amsterdam: University of Groningen, 2001.
8Wallace P. The psychology of the lnternet. New York: Cambridge University Press, 1999.
9Kou Z B, Zhang C S. Reply networks on a Bulletin Board System. Physical Review E[J],2003, Mar, 67.
10Jeong H, Neda Z, Barabasi A. Measuring preferential attachment in evolving networks. Europhys, 2003.
