St. Augustine, Dr. Howard Taylor, Mrs. Howard Taylor, Apostolic Fathers, J. Oswald Sanders (2010). “Moody Classics Complete Set”, p.1209, Moody Publishers
St. Augustine, Dr. Howard Taylor, Mrs. Howard Taylor, Apostolic Fathers, J. Oswald Sanders (2010). “Moody Classics Complete Set: Includes 19 Classics of the Faith in a Single Volume”, p.1326, Moody Publishers
Hannah Whitall Smith (2014). “The Christian's Secret of a Happy Life: Personal, Practical, and Powerful--An Invitation to Live Life at Its Most Blessed”, p.104, Barbour Publishing