Adam Smith (1843). “An Inquiry Into the Nature and Causes of the Wealth of Nations With a Life of the Author: Also a View of the Doctrine of Smith, Compared with that of the French Economists, with a Method of Facilitating the Study of His Works, from the French of M. Jariner”, p.28
Adam Smith (2007). “The Wealth of Nations: An Inquiry Into the Nature and Causes of the Wealth of Nations: With an introduction by Jonathan B. Wight, University of Richmond”, p.62, Harriman House Limited