1. Computer Generated Data and the Statistical Significance of Scalogram
2. A cognitive study of three fifth grade classrooms on selected Piagcttype tasks dealing with science related concepts. Unpublished doctoral dissertation. The University of Iowa, 1970.
3. A study of the structures of Piagetian logical and infralogical groupings within the concrete operational period. Unpublished doctoral dissertation, The University of Iowa, 1974.
4. Techniques of attitude scale construction. New York: Appleton-Century-Crofts, 1957, chap. 7.