Will Rogers, Bryan B. Sterling, Frances N. Sterling (1993). “Will Rogers' World: America's Foremost Political Humorist Comments on the Twenties and Thirties--and Eighties and Nineties”, p.53, Rowman & Littlefield
"Cargo Cult Science". Richard P. Feynman's Caltech commencement address (1974), as quoted in "'Surely You're Joking, Mr. Feynman!': Adventures of a Curious Character" edited by Ralph Leighton (p. 342), calteches.library.caltech.edu. 1985.