1. Dice, Eugene F. “The Influence of an Educational Awareness Experience on Components of Psychological Position Toward an Issue in Conservation: A Methodological Study,” unpublished EdD dissertation, The University of Michigan, 1965, p. 24.
2. George, Robert W. “A Comparative Analysis of Conservation Attitudes Where Conservation Education is a Part of the Educational Experience, research paper presented at the Technical Session of Conservation Education, North American Wildlife and Natural Resources Conference, San Francisco, California, March 14, 1967, pp. 10–11.
3. Hess, Robert D.; Torney, Judith V., The Development of Political Attitudes in Children, Anchor Books, Doubleday and Company, New York, 1967, pp.27–28, 120, 127, 201, 248, 249.
4. Raths, Louis E.; Harmin, Merril; Simon, Sidney, Values and Teaching, Charles E. Merril Publishing Company, Columbus, Ohio, 1966, p. 28–29.