↑ Rifkin, Jeremy (1995). The End of Work: The Decline of the Global Labor Force and the Dawn of the Post-Market Era. Putnam Publishing Group. tr. 66, 75. ISBN0-87477-779-8.
↑ Bennett, S. (1993). A History of Control Engineering 1930-1955. London: Peter Peregrinus Ltd. On behalf of the Institution of Electrical Engineers. ISBN0-86341-280-7.
↑ "Feedback and control systems" - JJ Di Steffano, AR Stubberud, IJ Williams. Schaums outline series, McGraw-Hill 1967
↑ Field, Alexander J. (2011). A Great Leap Forward: 1930s Depression and U.S. Economic Growth. New Haven, London: Yale University Press. ISBN978-0-300-15109-1<Factory productivity was greatly increased by electrification in the 1920s. Manufacturing productivity growth fell from 5.2%/yr 1919-29 to 2.76%/yr 1929-41. Field notes that spending on non-medical instruments increased significantly from 1929-33 and remained strong thereafter.)>
↑ Constable, George; Somerville, Bob (1964). A Century of Innovation: Twenty Engineering Achievements That Transformed Our Lives. Joseph Henry Press. ISBN0309089085.
↑ Landes, David. S. (1969). The Unbound Prometheus: Technological Change and Industrial Development in Western Europe from 1750 to the Present. Cambridge, New York: Press Syndicate of the University of Cambridge. tr. 475. ISBN0-521-09418-6.
