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.174
Leo Burnett (1961). “Communications of an Advertising Man: Selections from the Speeches, Articles, Memoranda, and Miscellaneous Writings of Leo Burnett”