1. Procedural and relational aspects of algebraic thinking;Arzarello,1991
2. The emergence and development of algebra in a problem solving context: A problem analysis;Bednarz,1994
3. Emergence and development of algebra as a problem-solving tool: Continuities and discontinuities with arithmetic;Bednarz,1996
4. Equations revisited;Booth,1987
5. Cognitive studies of algebra problem solving and learning;Chaiklin,1989