Gordon, T. (1975). P.E.T. Parent effectiveness Training: The tested new way to raise responsible children. Penguin.

Gordon, Thomas. P.E.T. Parent Effectiveness Training: The Tested New Way to Raise Responsible Children. New York: Penguin, 1975.

Gordon, Thomas. P.E.T. Parent Effectiveness Training: The Tested New Way to Raise Responsible Children. Penguin, 1975.