Bronfenbrenner, U.Two worlds of childhood: U.S. and U.S.S.R. New York: Russell Sage Foundation, 1970.
Fiske, E. College credits for real life.The New York Times, July 27, 1975.
Ginsburgh, H., & Opper, S.Piaget's theory of intellectual development. Englewood Clifs, N.J.: Prentice-Hall, 1970.
Maeroff, G. “College Age” is no longer just 18–22.The New York Times, April 20, 1975.
Olson, D., & Bruner, J. Learning through experience and learning through media. In D. Olson (Ed.),Media and symbols: The forms of expression, communication, and education. Chicago: The University of Chicago Press, 1974.
Wilson, R. C., Gaff, J. G.,et al. College professors and their impact on students. San Francisco: Jossey-Bass, 1975.