Mike Michalowicz (2008). “The Toilet Paper Entrepreneur: The Tell-it-like-it-is Guide to Cleaning Up in Business, Even If You are at the End of Your Roll”, p.112, Toilet Paper Entrepreneur
Thich Nhat Hanh (2009). “Touching the Earth: 46 Guided Meditations for Mindfulness Practice: Easyread Super Large 20pt Edition”, p.175, ReadHowYouWant.com