National Geographic Society. Special Publications Division. (1986). Builders of the ancient world: Marvels of engineering. The Society.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNational Geographic Society. Special Publications Division. Builders of the Ancient World: Marvels of Engineering. Washington, D.C: The Society, 1986.
एमएलए (9वां संस्करण) प्रशस्ति पत्रNational Geographic Society. Special Publications Division. Builders of the Ancient World: Marvels of Engineering. The Society, 1986.
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