1. this Journal.
2. This problem is treated in College Curriculum and Student Protest. Univ. Chicago Press, Chicago, in press.
3. Basic Principles of Curriculum and Instruction. Univ. Chicago Press: Syllabus Division, Chicago, 1950.
4. in The Teaching of Science, ( and , Eds.) Harvard Univ. Press, Cambridge, Mass., 1962, a, p. 34; b, p. 49.