Theodore Roosevelt (2015). “Theodore Roosevelt on Bravery: Lessons from the Most Courageous Leader of the Twentieth Century”, p.39, Skyhorse Publishing, Inc.
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