"The Ballot or The Bullet (Cleveland Version)". Malcolm X's speech at Cory Methodist Church in Cleveland, Ohio (April 3, 1964) as quoted in "Malcolm X Speaks: Selected Speeches and Statements" edited by George Breitman (pp. 23-44), 1965.
Samuel Rutherford (1848). “Letters of ... Samuel Rutherford, whith biogr. notices of his correspondents, by J. Anderson, and a sketch of his life, &c., by A.A. Bonar”, p.653