In addition to the references cited below, information about specific calculators is given in individual records. This list suggests both references found especially useful and the kind of sources those examining calculators may wish to consider. It is by no means complete.
Print Publications
Guy Ball and Bruce Flamm, The Complete Collector's Guide to Pocket Calculators, Tustin, CA: Wilson/Barnett Publishing, 1997.
Kathy B. Hamrick, “The History of the Hand-Held Electronic Calculator,” American Mathematical Monthly, 102, October 1996, pp. 633–639.
Peggy Aldrich Kidwell, Amy Ackerberg-Hastings, and David Lindsay Roberts, Tools of American Mathematics Teaching, Baltimore: Johns Hopkins University Press, 2008.
W.A.C. Mier-Jedrzejowicz, A Guide to HP Handheld Calculators and Computers, Tustin, California: Wilson/Burnett Publishing, 1997.
U.S. International Trade Commission, “In the Matter of Certain Electronic Calculators,” Investigation No. 337-7A-198, Washington, D.C, 1985.
Websites
Rick Bensene, The Old Calculator Web Museum, https://www.oldcalculatormuseum.com/
Casio International website, historical section, https://www.casio-intl.com/asia/en/calc/history/
Flow Simulation Ltd., The Calculator Home Page, https://www.calculator.org/
David G. Hicks, The Museum of HP Calculators, https://www.hpmuseum.org/
Viktor T. Toth, Programmable Calculators, https://www.rskey.org/CMS/
John Wolff, John Wolff’s Web Museum, Calculating Machines, https://www.johnwolff.id.au/index.htm
Bob Wolfson, Bob’s Calculators and Slide Rules, https://sites.google.com/site/bobscalculatorsandsliderules
Katherine Wasserman, [Digitized Calculator Manuals], https://www.wass.net/manuals/