APA (7th ed.) Citation

Allen, R. (2005). The cryptogram challenge: Over 150 codes to crack and ciphers to break. Thunder's Mouth Press.

Chicago Style (17th ed.) Citation

Allen, Robert. The Cryptogram Challenge: Over 150 Codes to Crack and Ciphers to Break. New York: Thunder's Mouth Press, 2005.

MLA (9th ed.) Citation

Allen, Robert. The Cryptogram Challenge: Over 150 Codes to Crack and Ciphers to Break. Thunder's Mouth Press, 2005.