Walter Lippmann, Clinton Rossiter, James Lare (1982). “The Essential Lippmann: A Political Philosophy for Liberal Democracy”, p.122, Harvard University Press
Lord Philip Dormer Stanhope Chesterfield, Philip Dormer Stanhope Earl of Chesterfield (1855). “The Works of Lord Chesterfield: Including His Letters to His Son, Etc : to which is Prefixed, an Original Life of the Author”, p.127