1. Dispensable and indispensable elements in Piaget's theory: On the core of Piaget's research program;Beilin,1985
2. The stage question in cognitive-developmental theory;Brainerd;Behavioral and Brain Sciences,1978
3. Intellectual development: Birth to adulthood;Case,1985
4. Horizontal structure in middle childhood: Cross-domain parallels in the course of cognitive growth;Case,1986
5. The development of children's understanding of proportions;Chapman;Child Development,1975