Cawley, J. F., et al. 1976. Project math. Tulsa, Oklahoma: Educational Progress Corporation.
2.
Cawley, J. F., et al. 1976. Mainstream: an instruction program. Tulsa, Oklahoma: Educational Progress Corporation.
3.
Cherkes, M. G., and Pianta, R.Logic test. In preparation.
4.
Mayer, W. V.1975. Planning and curriculum development. Boulder, Colorado: Biological Sciences Curriculum Study.
5.
Federal Register. November 19, 1976 (41 FR 52403).
6.
Flavell, J.1963. The developmental psychology of Jean Piaget. New York: Van Nostrand Reinhold.
7.
Furth, H. G., et al. 1970. Children's utilization of logical symbols: an inter pretation of conceptual behavior based on Piagetian theory. Developmental Psychology3:1, pp. 36–57.
8.
Gagne, R. M.1965. The conditions of learning. New York: Holt, Rinehart and Winston.
9.
Piaget, J., and Inhelder, B.1969. The psychology of the child. New York: Basic Books.
10.
Rosch, E., et al. 1976. Basic objects in natural categories. Cognitive Psychology8:382–439.
11.
Wason, P. C., and Johnson-Laird, P. N.1972. Psychology of reasoning. Cambridge, Massachusetts: Harvard University Press.