The reader of gentlemen's mail Herbert O. Yardley and the birth of American codebreaking - Kahn, David, 1930-; ebrary, Inc. (New Haven : Yale University Press, 2004)
Includes bibliographical references (p. 291-304) and index.
Electronic reproduction.
Keywords: Yardley, Herbert O. -- 1889-1958.; Cryptographers -- United States -- Biography; World War, 1914-1918 -- Cryptography; Electronic books