1. Maupin, Joseph T., and Vorthmann, Everett A., Solid State Keyboard, AFIPS Proceedings, 1969 Spring Joint Computer Conference, 34:149.
2. Ibid., July 27, 1971, United States Patent #3,596,144, Hall Effect Contactless Switch with Prebiased Schmitt Trigger.
3. Beer, A. C., May 1966, The Hall Effect and Related Phenomena, Solid State Electronics 9: 339.
4. Long, D., and Tufte, O. N., Honeywell Corporate Materials Science Center, private communication.
5. Kuhrt, F., and Hartel, W., 1969, Arch. Elektrotech. 43:1, cited in Weiss, H., “Structure and Application of Galvanomagnetic Devices,” Pergamon Press, Ltd., p. 96.