Derek Bok Center for Teaching and Learning, Harvard University. Working in Groups: A Guide for Harvard Faculty.

Kori Inkpen, Kellogg S. Booth, Maria Klawe, Rena Upitis. Playing Together Beats Playing Apart, Especially for Girls.

George M Jacobs, Christopher Ward, Patrick Gallo. The Dynamics of Digital Groups: Cooperative Learning in IT-Based Language Instruction.

Lawrence W. Sherman, Ph.D. Sociometry in the Classroom: How to Do It. Miami (Ohio) University,

Donald Walsh, Walsh's Classroom Sociometrics, 2004 (PC only).

Wikipedia entries:
Social Networks.