Malcolm X's speech at the Oxford Union debate (December 3, 1964) as quoted in Saladin Ambar "Malcolm X at Oxford Union: Racial Politics in a Global Era" (p. 44), 2013.
Richard Whately (2010). “Elements of Rhetoric: Comprising an Analysis of the Laws of Moral Evidence and of Persuasion, with Rules for Argumentative Composition and Elocution”, p.1, SIU Press