Blackwood, G. L., & Henry, J. (2009). Mysterious messages: A history of codes and ciphers. Dutton Children's Books.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBlackwood, Gary L., और Jason Henry. Mysterious Messages: A History of Codes and Ciphers. New York, N.Y.: Dutton Children's Books, 2009.
एमएलए (8वां संस्करण) प्रशस्ति पत्रBlackwood, Gary L., और Jason Henry. Mysterious Messages: A History of Codes and Ciphers. Dutton Children's Books, 2009.
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