1. Billett , Roy O. 1940. Fundamentals of Secondary-School Teaching, 671Boston: Houghton Mifflin Company. p. —,How To Make a Curriculum.Boston: Houghton Mifflin Company, 1924. 292 p.
2. Cairns , Laura . 1929. A Scientific Basis for Health Instruction in Public Schools, Vol. 2, 339–434. Berkeley, California: University of California Press. University of California Publications in Education, No. 5
3. Caldwell , O. W. and
Lundeen , G. E. 1932. Experimental Study of Superstitions and Other Unfounded Beliefs as Related to Certain Units of General Science, 138New York: Bureau of Publications, Teachers College, Columbia University.