F.B. Gilbreth, Bricklaying System, p. 150.

M.S. Read, An Introductory Psychology, pp. 179-194.

G.M. Stratton, Experimental Psychology and Culture, p. 42.

M.S. Read, An Introductory Psychology, p. 208.

William James, Psychology, Advanced Course, Vol. I, p. 667.

M.S. Read, An Introductory Psychology, pp. 212-213. William James, Psychology, Briefer Course, p. 302.

M.W. Calkins, A First Book in Psychology, p. 25.

James Sully, The Teacher's Handbook of Psychology, p. 290.

William James, Psychology, Briefer Course, p. 150.

W.D. Scott, Influencing Men in Business, chap. II.

Ibid., chap. III.

W.D. Scott, The Theory of Advertising, p. 71.

W.D. Scott, Increasing Human Efficiency in Business, p. 41.

G.M. Stratton, Experimental Psychology and Culture, p. 200.

F.W. Taylor, The Principles of Scientific Management, p. 36.