Mark Twain (2014). “Mark Twain on Common Sense: Timeless Advice and Words of Wisdom from America's Most-Revered Humorist”, p.8, Skyhorse Publishing, Inc.
William Shakespeare (2006). “The Poems: Venus and Adonis, The Rape of Lucrece, The Phoenix and the Turtle, The Passionate Pilgrim, A Lover's Complaint”, p.256, Cambridge University Press
Socrates, Plato, Aristotle (1967). “Wit and Wisdom of Socrates, Plato, Aristotle: Being a Treasury of Thousands of Glorious, Inspiring and Imperishable Thoughts, Views and Observations of the Three Great Greek Philosophers, Classified Under about Four Hundred Subjects for Comparative Study”