Stephen R. Covey (2015). “The Stephen R. Covey Interactive Reader - 4 Books in 1: The 7 Habits of Highly Effective People, First Things First, and the Best of the Most Renowned Leadership Teacher of our Time”, p.98, Mango Media Inc.
John Rosemond (1996). “Because I Said So!: A Collection of 366 Insightful and Thought- Provoking Reflections on Parenting and Family Life”, p.169, Andrews McMeel Publishing
John Flavel (1699). “The Method of Grace in Bringing Home the Eternal Redemption ... Being the Second Part of Gospel Redemption: Wherein the Great Mystery of Our Union and Communion with Christ is Opened and Applied ...”, p.238