Harlow Giles Unger. Improbable Patriot: The Secret History of Monsieur de Beaumarchais, the French Playwright Who Saved the American Revolution. Lebanon, NH: University Press of New England, 2011.
Thomas E. Chavez. Spain and the Independence of the United States: An Intrinsic Gift. Albuquerque: University of New Mexico Press, 2002.
Paul Lockhart. The Drillmaster of Valley Forge: The Baron de Steuben and the Making of the American Army. New York: Harper Collins, 2008.