Various. Scientific American Supplement, No. 803, May 23, 1891.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रVarious. Scientific American Supplement, No. 803, May 23, 1891.
एमएलए (9वां संस्करण) प्रशस्ति पत्रVarious. Scientific American Supplement, No. 803, May 23, 1891.
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