G. Davis, und M. Mcgowen. proceedings of the Annual Meeting of the 26th Annual Meeting of the International Group for the Psychology of Mathematics Education (PME), 2, Seite 273-280. Norwich, UK, University of Norwich, (Juli 2002)
M. Scaife, Y. Rogers, F. Aldrich, und M. Davies. CHI '97: Proceedings of the SIGCHI conference on Human factors in computing systems, Seite 343-350. New York, NY, USA, ACM Press, (1997)
D. Abrahamson. the Twenty Sixth Annual Meeting of the North American Chapter of the International Group for the Psychology of Mathematics Education, 2, Toronto, Ontario, Preney, (2004)