A. Paiva, I. Machado, and R. Prada. IUI '01: Proceedings of the 6th international conference on Intelligent user interfaces, page 129--136. New York, NY, USA, ACM Press, (2001)
A. Sfard. Proceedings of 21st Conference of PME-NA, page 23-44. Columbus, Ohio, Clearing House for Science, mathematics, and Environmental Education, (2001)
F. Arzarello. the 24th Conference of the International Group for the Psychology of Mathematics Education (PME), 1, page 23--38. Hiroshima, Japan, (2000)
C. Nehaniv. Narrative Intelligence: Papers from the 1999 AAAI Fall Symposium, (5-7 November 1999 - North Falmouth, Massachusetts), page 101-104. AAAI Press, Technical Report FS-99-01, (1999)
C. Sackur, T. Assude, and M. Maurel. European Research in Mathematics Education I.I + I.II Proceedings of the First Conference of the European Society for Research in Mathematics Education, 1 & 2, Osnabrueck, Forschungsinstitut fuer Mathematikdidaktik, (1999)