Sure, how about some classics like: The Didache Anselm, Cur Deus Homo Anselm, Proslogion Augustine, City of God Augustine, Confessions Augustine, On Chris

Sure, how about some classics like: The Didache Anselm, Cur Deus Homo Anselm, Proslogion Augustine, City of God Augustine, Confessions Augustine, On Christian Doctrine William Law, A Serious Call to a Devout and Holy Life Luther, The Bondage of the Will Calvin, Institutes of the Christian Religion Pascal, Pensées All of these are in public domain.