Various. Scientific American Supplement, No. 810, July 11, 1891.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रVarious. Scientific American Supplement, No. 810, July 11, 1891.
एमएलए (9वां संस्करण) प्रशस्ति पत्रVarious. Scientific American Supplement, No. 810, July 11, 1891.
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