Attributed in Reader's Digest, Sept. 1937. The attribution to Twain is obviously spurious because Twain's father died when the future writer was eleven years old.
Euripides (1958). “Euripides: Hecuba, translated by W. Arrowsmith. Andromache, translated by J. F. Nims. The Trojan women, translated by R. Lattimore. Ion, translated by R. F. Willetts”
Marcus Tullius Cicero, Pliny (2010). “Letters of Marcus Tullius Cicero with His Treatises on Friendship and Old Age: Letters of Pliny the Younger”, p.13, Cosimo, Inc.
"George Washington’s Farewell Address". "The Life of George Washington. Special Edition for Schools", ed. Robert Faulkner and Paul Carrese, Indianapolis: Liberty Fund, oll.libertyfund.org. 2000.
Alexander Hamilton, John Church Hamilton (1850). “The Works of Alexander Hamilton: Miscellanies, 1774-1789: A full vindication; The farmer refuted; Quebec bill; Resolutions in Congress; Letters from Phocion; New-York Legislature, etc”, p.447