Maximus the Confessor:
Opuscula

Source Used:   Ante-Nicene Fathers: The Writings of the Fathers Vol. I – Vol. X and Nicene and Post-Nicene Fathers: Series I,  Vol. I – Vol. XIV & Series II, Vol. I – Vol. XIV.  Edited by Alexander Roberts, James Donaldson, and A. Cleveland Coxe. (Buffalo, NY: Christian Literature Publishing Co., 1885.)