Butler lhWilliam S. & Keeney. Secret messages: Concealment, codes, and other types of ingenious communication.
Chicago Style (17th ed.) CitationButler lhWilliam S. and Keeney. Secret Messages: Concealment, Codes, and Other Types of Ingenious Communication. New York lbSimon & Schuster lc2001.
MLA (9th ed.) CitationButler lhWilliam S. and Keeney. Secret Messages: Concealment, Codes, and Other Types of Ingenious Communication.
Warning: These citations may not always be 100% accurate.