Crichton, M. (1987). Sphere: A novel. Knopf.
Lua i Stíl Chicago (17ú heag.)Crichton, Michael. Sphere: A Novel. New York: Knopf, 1987.
Lua MLA (8ú heag.)Crichton, Michael. Sphere: A Novel. Knopf, 1987.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.