Kuhlen, R. G., & Thompson, G. G. (1970). Psychological studies of human development (3rd.ed.). Appleton-century-crofts.

Kuhlen, Raymond G., and George G. Thompson. Psychological Studies of Human Development. 3rd.ed. New York: Appleton-century-crofts, 1970.

Kuhlen, Raymond G., and George G. Thompson. Psychological Studies of Human Development. 3rd.ed. Appleton-century-crofts, 1970.