1. The nature of the process conception of function;Dubinsky,1992
2. Graphiques et equations: l'Articulation de deux registres;Duval;Annales de Didactique et de Sciences Cognitives,1988
3. On the development of a sense for functions;Eisenberg,1992
4. The construction of function, contradiction and proof;Hitt,1989
5. Problems of representation in the teaching and learning of mathematics,1987