A. J. Muste's statement of 1941, as quoted in Howard Zinn "A People's History" (p. 416), 1980, and later quoted in Howard Zinn "The Twentieth Century: A People's History" (p. 159), May 9, 1984.
"Letters to Atticus" (1st century B.C.), as quoted in "Words on war: military quotations from ancient times to the present", book by Jay M. Shafritz, 1990.