1. Anonymous, Bethleham torque amplifier, Am. Mach. 66 (1927) 889–897.
2. W.F. Aspray, A.W. Burks (Eds.), Papers of John Von Neumann on Computing and Computer Theory, MIT Press, Cambridge, MA, 1987.
3. J.V. Atanasoff, Computing Machine for the Solution of Large Systems of Linear Algebraic Equations, Unpublished, August 1940, Published in Randell, 1973, pp. 305–325.
4. J.G. Brainerd, J.P. Eckert, J.W. Mauchly, Report on an Electronic Diff∗ Analyzer, for Ballistic Research Laboratory, Aberdeen Proving Ground, by Moore School of Electrical Engineering, University of Pennsylvania, Unpublished, April 1943. Copies in Moore School Papers and ENIAC Patent Trial Records.
5. A.R. Burks, A.W. Burks, The First Electronic Computer—The Atanasoff Story, The University of Michigan Press, Ann Arbor, MI, 1988.