Wayne W. Dyer (2009). “Your Erroneous Zones: Step-by-Step Advice for Escaping the Trap of Negative Thinking and Taking Control of Your Life”, p.30, Harper Collins
Wayne W. Dyer (2009). “The Invisible Force: 365 Ways to Apply the Power of Intention to Your Life: Easyread Large Bold Edition”, p.17, ReadHowYouWant.com