Mark Twain (1869). “The Innocents Abroad, Or, The New Pilgrims' Progress: Being Some Account of the Steamship Quaker City's Pleasure Excursion to Europe and the Holy Land : with Descriptions of Countries, Nations, Incidents, and Adventures as They Appeared to the Author”, p.546
H. Jackson Brown, Jr. (2012). “Life's Little Instruction Book: Simple Wisdom and a Little Humor for Living a Happy and Rewarding Life”, p.277, Thomas Nelson Inc