Scott Ramsay. "Ensuring Benevolent Neutrality: The British Government's Appeasement of General Franco during the Spanish Civil War, 1936-1939". International History Review 41:3 (2019): 604–623. DOI: https://doi.org/10.1080/07075332.2018.1428211.
Bowers, Claude G. (1954). My Mission to Spain: Watching the Rehearsal for World War II. New York: Simon and Schuster. pp. 411–412. LCCN54006668.
nybooks.com
Dan Kaufman (24 February 2022). "Soldiers of Solidarity". The New York Review. Kaufman writes: "It was the first time in American history that the US refused to sell arms to a legally elected government."