Mark Twain (2014). “Mark Twain on Common Sense: Timeless Advice and Words of Wisdom from America's Most-Revered Humorist”, p.17, Skyhorse Publishing, Inc.
Mark Twain, Charles Neider (1961). “Life as I find it [by] Mark Twain [pseud.] Essays, sketches, tales, and other material, the majority of which is now published in book form for the first time: edited, with an introd. and notes”