Here are a few books that a student of the Holy Trinity may find helpful; some of them contain suggested readings for those who take the course for credit.
Aquinas, St. Thomas, Summa Theologica, Part I, Questions 27-43.
Augustine, St., De Trinitate (On the Trinity).
Catechism of the Catholic Church (The Catholic Book Publishing Co., New York, 1994).
Farmer, William A., The International Bible Commentary (The Liturgical Press, Collegeville, Minn. 1998).
Jesuit Fathers of St. Mary's College, The Church Teaches. Documents of the Church in English Translation. (Tan Books, P. O. Box 424, Rockford, IL 61105). (Contains most of the important references to Denzinger -- in English).
Jurgens, William A., The Faith of the Early Fathers. Three Volumes. (The Liturgical Press, Collegeville, Minn., 1979). (Contains most of the references to the Fathers of the Church -- in English. This is the English translation of Rouet de Journel, Enchiridion Patristicum.)
New Catholic Encyclopedia. Fifteen Volumes (1967). Select articles on aspects of the Trinity.
Ott, Ludwig, Fundamentals of Catholic Dogma, pp. 50-75. (Tan Books).