Κynigos, C., & Psycharis, G. (2003). 13 year-olds’ meanings around intrinsic curves with a medium for symbolic expression and dynamic manipulation. In N. Paterman, Dougherty, B., & Zilliox, J. (Eds.), Proceedings of the 27th Conference of the International Group for the Psychology of Mathematics Education (PME 27) (Vol. 3, pp. 165-172). CRDG, College of Education, University of Hawai’I, Honolulu, U.S.A. Hawaii.