(en) M. Keith Booker, Historical Dictionary of Science Fiction in Literature, Rowman & Littlefield, , 434 p. (ISBN9780810878846, lire en ligne), p. 332
google.fr
(en) Daniel Eagan, America's Film Legacy: The Authoritative Guide To The Landmark Movies In The National Film Registry, Continuum International Publishing Group Ltd., (ISBN978-0826429773, lire en ligne), p. 477
nytimes.com
(en) Marjorie Burger, « Jay Williams and Raymond Abrashkin. Illustrated by Ezra Jack Keats. 144 pp. New York: Whittlesey House. $2.95. For Ages 8 to 12 », The New York Times, (lire en ligne)