1. The early growth of logic in the child: Classification and seriation;Inhelder,1964
2. Psychology of the child;Piaget,1969
3. Children and adolescents: Interpretive essays on Jean Piaget;Elkind,1974
4. A study of the conservation of substance in the junior school child;Lovell;British Journal of Educational Psychology,1960
5. The child's conception of the world;Piaget,1929