Wallace D. Wattles (2015). “Wallace D. Wattles Ultimate Collection – 10 Books in One Volume: The Science of Getting Rich, The Science of Being Well, The Science of Being Great, How to Get What You Want and more: From one of the New Thought pioneers, author of Making of the Man Who Can or How to Promote Yourself and New Science of Living and Healing or Health Through New Thought and Fasting”, p.68, e-artnow
Lloyd J. Thomas, Patrick Williams (2011). “Total Life Coaching: 50+ Life Lessons, Skills, and Techniques to Enhance Your Practice . . . and Your Life”, p.2, W. W. Norton & Company