1. The effect of problem structure on the processes used by concrete- and formal-operational students to solve verbal mathematics problems. Unpublished doctoral dissertation, Purdue University, 1977.
2. A new approach to data-analysis for the construction of Piagetian tests. Paper presented at the meeting of the American Educational Research Association, Boston, April 1980.
3. The Karplus Islands Puzzle: Does it measure piagetian operations?
4. The effects of sequencing manipulative activities on the concepts learning of adolescents. Doctoral dissertation, State University of New York at Albany, 1977. Dissertation Abstracts International, 1977, 38(5), 2626-A. (University Microfilms No. 77-24,877.)
5. The developmental Psychology of Jean Piaget. Princeton, VA: Nostrand, 1963.