APA (7th ed.) Citation

Tharp, R. G., & Wetzel, R. J. (1969). Behavior modification in the natural environment. Academic Press.

Chicago Style (17th ed.) Citation

Tharp, Roland G., and Ralph J. Wetzel. Behavior Modification in the Natural Environment. New York: Academic Press, 1969.

MLA (9th ed.) Citation

Tharp, Roland G., and Ralph J. Wetzel. Behavior Modification in the Natural Environment. Academic Press, 1969.