Marx, M. H., & Hillix, W. A. (1979). Systems and theories in psychology (3rd ed.). Mc-Graw-Hill.

Marx, Melvin H., and William A. Hillix. Systems and Theories in Psychology. 3rd ed. New York: Mc-Graw-Hill, 1979.

Marx, Melvin H., and William A. Hillix. Systems and Theories in Psychology. 3rd ed. Mc-Graw-Hill, 1979.