Ray, W. J., & Ravizza, R. (1988). Methods toward a science of behavior and experience (3rd ed.). Wadsworth Publ. Co..

Ray, William J., and Richard Ravizza. Methods Toward a Science of Behavior and Experience. 3rd ed. Belmont, Calif.: Wadsworth Publ. Co., 1988.

Ray, William J., and Richard Ravizza. Methods Toward a Science of Behavior and Experience. 3rd ed. Wadsworth Publ. Co., 1988.