David Brainerd (1824). “The Life of the Rev. David Brainerd, Missionary to the Indians, from the Society in Scotland, for Propagating Christian Knowledge: Who Died at Northampton, in New-England, October 9, 1747, in the 30th Year of His Age”, p.291
M. Scott Peck (2002). “The Road Less Traveled, 25th Anniversary Edition: A New Psychology of Love, Traditional Values, and Spiritual Growth”, p.42, Simon and Schuster