Booker T. Washington (1901). “An Autobiography: The Story of My Life and Work, the Original Brought Up-to-date with Over Half a Hundred Full Page Photo and Halftone Engravings and Drawings by Frank Beard”
Quoted in Evan Esar, The Dictionary of Humorous Quotations (1949). Colonel Tom Parker, Elvis Presley's manager, is said to have remarked, "You don't have to be nice to people you meet on the way up if you're not coming back down again."
Theodore Roosevelt (2015). “Theodore Roosevelt on Bravery: Lessons from the Most Courageous Leader of the Twentieth Century”, p.4, Skyhorse Publishing, Inc.