General Sources

Aquinas, Thomas. Summa Contra Gentiles
Aquinas, Thomas. Summa Theologiae
Aristotle. Nicomachean Ethics
Aristotle. Politics
Aristotle. Metaphysics 
Burtt, E. A. The Metaphysical Foundations of Modern Physical Science
Craig, William Lane. Time and Eternity: Exploring God's Relationship to Time
Feser, Edward. Neo-Scholastic Essays
Feser, Edward. Scholastic Metaphysics
Feser, Edward. Locke
Feser, Edward. Aquinas
Feser, Edward. Philosophy of Mind: An Introduction
Geisler, Norman. Christian Apologetics
Geisler, Norman. Systematic Theology
Gilson, Etienne. The  Unity of Philosophical Experience
Gilson, Etienne. Methodical Realism
Gilson, Etienne. Thomist Realism and the Critique of Knowledge
Girgis, Sherif. What is Marriage?
Kreeft, Peter. Socratic Logic, 3rd. ed.
Mansfield, Harvey C. A Student's Guide to Political Philosophy
Marsden, George M. The Outrageous Idea of Christian Scholarship
Moreland, J. P. Christianity and the Nature of Science
Oderberg, David. Real Essentialism
Schall, James V. Another Sort of Learning
Schall, James V. At the Limits of Political Philosophy
Simon, Yves. Freedom of Will
Simon, Yves. A General Theory of Authority
Sowell, Thomas. Basic Economics.
Stauss, Leo and Joseph Cropsey, eds. The History of Political Philosophy 

Strauss, Leo. What Is Political Philosophy?