Belfield, R. (2007). The six unsolved ciphers: Inside the mysterious codes that have confounded the world's greatest cryptographers. Ulysses.
Chicago-Zitierstil (17. Ausg.)Belfield, Richard. The Six Unsolved Ciphers: Inside the Mysterious Codes That Have Confounded the World's Greatest Cryptographers. Berkeley, Calif: Ulysses, 2007.
MLA-Zitierstil (9. Ausg.)Belfield, Richard. The Six Unsolved Ciphers: Inside the Mysterious Codes That Have Confounded the World's Greatest Cryptographers. Ulysses, 2007.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.