1. Aquinas, T. (1964). Summa theologiae: Latin text and English translation, introductions, notes, appendices, and glossaries (T. Gilby, Ed.). New York: McGraw-hill.
2. Dubay, T. (1989). Fire within. San Francisco: Ignatius Press.
3. May, G. (2009). The dark night of the soul: A psychiatrist explores the connection between darkness and spiritual growth. New York: HarperOne.
4. Norris, K. (2008). Acedia and me: A marriage, monks, and a writer’s life. New York: Riverhead Books.
5. Phillips, A. (1993). On kissing, tickling, and being bored: Psychoanalytic essays on the unexamined life. Cambridge: Harvard University Press.