1. The origins of intelligence in children;Piaget,1952
2. The construction of reality in the child;Piaget,1954
3. Genetic epistemology;Piaget,1970
4. Development of object permanence in visually impaired infants;Rogers;J Vis Impair Blind,1988
5. Handicap and cognition: visual deprivation and the rate of motor development in infants;Gillman;New Outlook Blind,1973