Theodore Roosevelt (2015). “Theodore Roosevelt on Bravery: Lessons from the Most Courageous Leader of the Twentieth Century”, p.36, Skyhorse Publishing, Inc.
Theodore Roosevelt (2015). “Theodore Roosevelt on Bravery: Lessons from the Most Courageous Leader of the Twentieth Century”, p.44, Skyhorse Publishing, Inc.
Theodore Roosevelt, Eugene Thwing (1919). “Newer Roosevelt messages: speeches, letters and magazine articles dealing with the war, before and after, and other vital topics”
Address at the Sorbonne, Paris, 23 Apr. 1910. Richard M. Nixon quoted this passage in his address to the nation announcing his decision to resign the presidency, 8 Aug. 1974. See Theodore Roosevelt 1; Theodore Roosevelt 2; Theodore Roosevelt 5