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”
Henry David Thoreau (2014). “Citizen Thoreau: Walden, Civil Disobedience, Life Without Principle, Slavery in Massachusetts, A Plea for Captain John Brown”, p.133, Graphic Arts Books