National Geographic Society (U.S.) Special Publications Division. (1979). Mysteries of the ancient world. The Society.
Lua i Stíl Chicago (17ú heag.)National Geographic Society (U.S.) Special Publications Division. Mysteries of the Ancient World. Washington: The Society, 1979.
Lua MLA (9ú heag.)National Geographic Society (U.S.) Special Publications Division. Mysteries of the Ancient World. The Society, 1979.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.