"Clayton, Jo", Harris M. Lentz, Obituaries in the Performing Arts, 1998, Jefferson, North Carolina: McFarland, 1999, ISBN978-0-7864-5203-3, p. 46.
Bernard A. Drew, Literary Afterlife: The Posthumous Continuations of 325 Authors' Fictional Characters, Jefferson, North Carolina: McFarland, 2010, ISBN978-0-7864-4179-2, p. 279.