D. Ingalls, T. Kaehler, J. Maloney, S. Wallace, and A. Kay. OOPSLA '97: Proceedings of the 12th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications, page 318-326. New York, NY, ACM Press, (1997)
K. Sedighian, and A. Sedighian. 18th Annual Meeting of the International Group for the Psychology of Mathematics Education -- the North American Chapter, Florida, USA, (1996)
M. Klawe, and E. Phillips. CSCL '95: The first international conference on Computer support for collaborative learning, page 209--213. Mahwah, NJ, USA, Lawrence Erlbaum Associates, Inc., (1995)