Lord Philip Dormer Stanhope Chesterfield, Philip Dormer Stanhope Earl of Chesterfield (1855). “The Works of Lord Chesterfield: Including His Letters to His Son, Etc : to which is Prefixed, an Original Life of the Author”, p.312
Wayne D. Dosick (2000). “The Business Bible: 10 New Commandments for Bringing Spirituality & Ethical Values Into the Workplace”, p.46, Jewish Lights Publishing
"127 Hours: Director Danny Boyle Says You’d Cut Your Hand Off, Too". Interview with Mary Anne Potts, adventureblog.nationalgeographic.com. November 4, 2010.