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. Mariotti. Proceedings of the 22nd Conference of the International Group for the Psychology of Mathematics Education, 1, page 180--195. Stellenbosch, South Africa, PME, University of Stellenbosch, (July 1998)
R. Goldstein, and D. Pratt. Proceedings of the 25th Conference of the International Group for the Psychology of Mathematics Education (PME25), 3, page 49--56. PO Box 9432, 3506 GK Utrecht, The Netherlands, Freudenthal Institute, Faculty of Mathematics and Computer Science, Uthrect University, (July 2001)
A. Stern, and M. Mateas. the International DiGRA Conference, June 16th - 20th, 2005, Vancouver, British Columbia, Canada (http://www.gamesconference.org/digra2005/overview.php), (2005)