Adam Smith, Jean-Baptiste Say, J.R. McCulloch (2013). “History of Economic Theory: The Selected Writings of Adam Smith, Jean-Baptiste Say, and J.R. McCulloch”, p.133, Coventry House Publishing
William Fleming, Charles Porterfield Krauth (1860). “The Vocabulary of Philosophy, Mental, Moral and Metaphysical: With Quotations and References; for the Use of Students”, p.95