Friedman, W. F., & Friedman, E. (1957). The Shakespearean ciphers examined: An analysis of cryptographic systems used as evidence that some author other than William Shakespeare wrote the plays commonly attributed to him (Repr.). Univ. Press.
Chicago Style (17th ed.) CitationFriedman, William F., and Elizabeth Friedman. The Shakespearean Ciphers Examined: An Analysis of Cryptographic Systems Used as Evidence That Some Author Other than William Shakespeare Wrote the Plays Commonly Attributed to Him. Repr. Cambridge: Univ. Press, 1957.
MLA (9th ed.) CitationFriedman, William F., and Elizabeth Friedman. The Shakespearean Ciphers Examined: An Analysis of Cryptographic Systems Used as Evidence That Some Author Other than William Shakespeare Wrote the Plays Commonly Attributed to Him. Repr. Univ. Press, 1957.