Burden trends in modern management / by N.M. Perris ... Perris, N. M. Industrial efficiency. T58 .P38 658 WAM "Presented at the A.M.A. Production conference ... Cleveland, June 9, 1930"--P. 2. Discussion: p. 18-28. New York, N.Y.: American management association, c1937. c1937. 1930 Text 28 p. eng [American management association] Production series: Pro. 85 Production series (American Management Association) ; Pro. 85.