Carter, A. A., & Gould, S. J. (1999). The art of national geographic: Century of illustration (Special catalog edition.). National Geographic Society.
Lua i Stíl Chicago (17ú heag.)Carter, Alice A., agus Stephen Jay Gould. The Art of National Geographic: Century of Illustration. Special catalog edition. Washington, D.C.: National Geographic Society, 1999.
Lua MLA (9ú heag.)Carter, Alice A., agus Stephen Jay Gould. The Art of National Geographic: Century of Illustration. Special catalog edition. National Geographic Society, 1999.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.