"An Additional Number of Letters to the Republican". Letters by the Federal Farmer (pseudonym of Richard Henry Lee), Letter XVIII, teachingamericanhistory.org. January 25, 1988.
John Esten Cooke, Robert E. Lee (2017). “General Robert E. Lee: The True Story of the Infamous “Marble Man”: The Life & Legacy of Robert E. Lee, Including & Personal Writings, Speeches and Orders”, p.42, Madison & Adams