[ 1]. Charles Babbage, Economy of Manufacturers. Preface, p. v.

[ 2]. Halbert P. Gillette, Paper No. 1, American Society of Engineering Contractors.

[ 3]. Gillette and Dana, Cost Keeping and Management, p. 5.

[ 4]. F.B. Gilbreth, Motion Study, p. 98.

[ 5]. F.W. Taylor, Principles of Scientific Management, p. 144.

[ 6]. F.W. Taylor, Shop Management, para. 16, Am. Soc. M.E., Paper No. 1003.

[ 7]. William James, Psychology, Vol. I, p. 258.

[ 8]. F.B. Gilbreth, Cost Reducing System, Chap. 1.

[ 9]. Morris Llewellyn Cooke, Bulletin No. 5 of the Carnegie Foundation for the Advancement of Teaching, p. 17.

[10]. F.W. Taylor, Shop Management, para. 234, Am. Soc. M.E., Paper No. 1003.