John Stuart Mill (2017). “JOHN STUART MILL - Ultimate Collection: Works on Philosophy, Politics & Economy (Including Memoirs & Essays): Autobiography, Utilitarianism, The Subjection of Women, On Liberty, Principles of Political Economy, A System of Logic, Ratiocinative and Inductive and More”, p.215, Madison & Adams
John Stuart Mill “Principles of Political Economy: Abridged with Critical, Bibliographical and Explanatory Notes and a Sketch of the History of Political Economy”, Library of Alexandria