Gary Stanley Becker, Hoover Institution on War, Revolution, and Peace (1996). “The Economic Way of Looking at Behavior: The Nobel Lecture”, p.9, Hoover Press
Jeremy Taylor (1850). “Holy Living and Dying: Together with Prayers : Containing the Whole Duty of a Christian, and the Parts of Devotion Fitted to All Occasions and Furnished for All Necessities”, p.58