Dorling Kindersley Limited. (2015). When on Earth?: History as you've never seen it before (First American edition.). DK Publishing.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रDorling Kindersley Limited. When on Earth?: History as You've Never Seen It Before. First American edition. New York, New York: DK Publishing, 2015.
एमएलए (8वां संस्करण) प्रशस्ति पत्रDorling Kindersley Limited. When on Earth?: History as You've Never Seen It Before. First American edition. DK Publishing, 2015.
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