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)
D. Carraher, and D. Earnest. Proceedings of the 2003 Joint Meeting of PME and PMNA (PME27 and PME-NA25), 2, page 173--180. 1776 University Av., Honolulu, HI 96822, International Group for the Psychology of Mathematics Education, College of Education, University of Hawai'i, (July 2003)
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)
R. Masoon, and J. Macfeetors. proceedings of 2002 annual meeting of the Canadian Mathematics Education Study Group, page 143--144. Queen's University, (May 2002)
M. Mosimege. Proceedings of the 22nd Conference of the International Group for the Psychology of Mathematics Education, 3, page 279--286. Stellenbosch, South Africa, PME, University of Stellenbosch, (July 1998)