1. The hierarchical structure of formal operational tasks;Bart;Applied Psychological Measurement,1979
2. Memorizing: A test of untrained mildly retarded children's problem solving;Belmont;American Journal of Mental Deficiency,1982
3. Validating theories of intelligence;Butterfield,1980
4. Piaget and beyond: Toward a developmentally based theory and technology of instruction;Case,1978
5. Eliciting formal operations;Danner;Child Development,1977