W. James, The Principles of Psychology (New York: Henry Holt, 1890); I. P. Pavlov, Conditioned Reflexes (Oxford: Oxford University Press, 1927); E. L. Thorndike, Animal Intelligence (New York: Macmillan, 1911); B. F. Skinner, The Behavior of Organisms: An Experimental Analysis (New York: Appleton-Century-Crofts, 1938).
