Gordon, H. (2021). Notes from deep time: A journey through our past and future worlds. Profile Books.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रGordon, Helen. Notes from Deep Time: A Journey Through Our Past and Future Worlds. London: Profile Books, 2021.
एमएलए (9वां संस्करण) प्रशस्ति पत्रGordon, Helen. Notes from Deep Time: A Journey Through Our Past and Future Worlds. Profile Books, 2021.
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