(en) Richard Allen Morton, Roger C. Sullivan and the Making of the Chicago Democratic Machine, 1881-1908, McFarland, (ISBN9781476663777, lire en ligne), p. 104
(en) Richard C. Lindberg, The Gambler King of Clark Street: Michael C. McDonald and the Rise of Chicago's Democratic Machine, SIU Press, (ISBN978-0-8093-8654-3, lire en ligne), p. 141