Andrew Weil, M.D. (2013). “8 Weeks to Optimum Health: A Proven Program for Taking Full Advantage of Your Body's Natural Healing Power”, p.20, Ballantine Books
Andrew Weil, M.D. (2011). “Spontaneous Healing: How to Discover and Enhance Your Body's Natural Ability to Maintain and Heal Itself”, p.127, Ballantine Books