Max Beckmann, Barbara Copeland Buenger (1997). “Self-Portrait in Words: Collected Writings and Statements, 1903-1950”, p.305, University of Chicago Press
David Ricardo, John Ramsay McCulloch (1846). “The Works of David Ricardo, Esq., M.P.: With a Notice of the Life and Writings of the Author”, p.31, London, J. Murray
Mercy Otis Warren (1805). “History of the Rise, Progress, and Termination of the American Revolution: Interspersed with Biographical, Political and Moral Observations”, p.4