1. Aquinas, Thomas. 1948. Summa Theologica. 5 vols. Translated by the Fathers of the English Dominican Province. New York: Benziger.
2. ———. 1975. Summa Contra Gentiles. Vol. 3: Providence, pt. 2. Translated by Vernon J. Bourke. South Bend, IN: University of Notre Dame Press.
3. ———. 2002. On Law, Morality, and Politics. Translated by Richard J. Regan. Edited by William P. Baumgarth and Richard J. Regan. 2nd ed. Indianapolis, IN: Hackett.
4. Boonin, David. 2008. The Problem of Punishment. Cambridge: Cambridge University Press.
5. Cronin, Michael. 1939. The Science of Ethics. Vol. 1: General Ethics. Dublin: Gill.