Richard Whately (1858). “Elements of Rhetoric: Comprising an Analysis of the Laws of Moral Evidence and of Persuasion : with Rules for Argumentative Composition and Elocution”, p.247
Richard Whately (1846). “Elements of Rhetoric: Comprising an Analysis of the Laws of Moral Evidence and of Persuasion, with Rules for Argumentative Composition and Elocution”, p.394