"A 4th Course of Chicken Soup for the Soul: More Stories to Open the Heart and Rekindle the Spirit". Book by Jack Canfield (p. 188), September 1, 2012.
Orison Swett Marden (2015). “He Can Who Thinks He Can, and Other Papers on Success in Life: From the Renowned Author of Inspirational Works like How to Get what You Want, Prosperity and How to Get It, The Miracles of Right Thought, Self-Investment and Masterful Personality”, p.27, e-artnow