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
"The American Soul: An Appreciation of the Four Greatest Americans and their Lessons for Present Americans". Book by Charles Sherwood Farriss, p. 63, 1920.