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”
Marcus Tullius Cicero (1855). “Cicero's Three books of offices, or moral duties: also his Cato Major, an essay on old age; Lælius, an essay on friendship; Paradoxes; Scipio's dream; and Letter to Quintus on the duties of a magistrate”, p.203