Summa Theologica - Part I Q38-41: Of the Name of the Holy Ghost, as Gift - Of the Persons in Reference to the Notional Acts

The Summa Theologica (or the Summa Theologiae or simply the Summa, written 1265–1274) is the most famous work of Thomas Aquinas although it was never finished. It was intended as a manual for beginners as a compilation of all of the main theological teachings of that time. It summarizes the reasonings for almost all points of Christian theology in the West, which, before the Protestant Reformation, subsisted solely in the Roman Catholic Church. The Summa's topics follow a cycle: the existence of God, God's creation, Man, Man's purpose, Christ, the Sacraments, and back to God. (Summary adapted from the Wikipedia)

 38. Of the Name of the Holy Ghost, as Gift

 39. Of the Persons in Relation to the Essence

 40. Of the Persons as Compared to the Relations or Properties

 41. Of the Persons in Reference to the Notional Acts