1. Aristotle: 1984, The Complete Works of Aristotle, ed. J. Barnes (Princeton University Press, Princeton).
2. Augustine, St.: 1909, The Confessions of St. Augustine, in Charles W. Eliot (ed.), Harvard Classics, Vol. 7. (P.F. Collier & Son, New York).
3. Cicero: 1961, De Natura Deorum, trans. H. Rackham (Harvard University Press, Cambridge).
4. Cicero: 1976, On the Commonwealth, trans. G. H. Sabine and S. B. Smith (Macmillan, New York).
5. Cicero: 1983, De Finibus Bonorum et Malorum, trans. H. Rackham (Harvard University Press, Cambridge).