Fred B. Wrixon

• 2440 questions and answers
• Codes, Ciphers, Secrets and Cryptic Communication
• Codes, Chiffren & andere Geheimsprachen
• Codes and ciphers
• Codes, ciphers & other cryptic & clandestine communication
• Codes, ciphers, and secret languages
• 2440 Question Answer Enter Entic &
• Codes Ciphers and Other Cryptic and Clandestine Communcitioan; Making and Breaking Secret Messages from Hieroglyphs to the Internest (Other Cryptic & Clandestine Communication)
• Codes, ciphers and secret language
• Harrap's Books of Codes, Ciphers, amd secret Languages