Crichton, M. (1987). Sphere: A novel. Ballantine Books.
Lua i Stíl Chicago (17ú heag.)Crichton, Michael. Sphere: A Novel. New York: Ballantine Books, 1987.
Lua MLA (9ú heag.)Crichton, Michael. Sphere: A Novel. Ballantine Books, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.