^Editors of the American Heritage Dictionaries, eds. The American Heritage Guide to Contemporary Usage and Style. Houghton Mifflin Harcourt, 2005. ISBN978-0618604999 p. 119.
^Charles Harrington Elster. The Big Book of Beastly Mispronunciations: The Complete Opinionated Guide for the Careful Speaker. 2nd ed. Houghton Mifflin, 2006. ISBN978-0618423156 pp. 110–111.