APA (7th ed.) Citation

Hardy, R. E., & Cull, J. G. (1974). Modification of behavior of the mentally retarded: Applied principles. Thomas.

Chicago Style (17th ed.) Citation

Hardy, Richard E., and John G. Cull. Modification of Behavior of the Mentally Retarded: Applied Principles. Springfield, Ill: Thomas, 1974.

MLA (9th ed.) Citation

Hardy, Richard E., and John G. Cull. Modification of Behavior of the Mentally Retarded: Applied Principles. Thomas, 1974.