Henry Ward Beecher, Augusta Moore (1859). “Notes from Plymouth Pulpit: A Collection of Memorable Passages from the Discourses of Henry Ward Beecher, with a Sketch of Mr. Beecher and the Lecture Room”, p.41
Theodore Roosevelt (2015). “Theodore Roosevelt on Bravery: Lessons from the Most Courageous Leader of the Twentieth Century”, p.44, Skyhorse Publishing, Inc.