. pp. 775–6. ISBN 978-0-684-83130-5). {{cite book}}: Check |isbn= value: invalid character (help)↑ Kahn, David (1967). The Codebreakers. pp. 631–2. ISBN 978-0-684-83130-5). {{cite book}}: Check |isbn= value: invalid character (help)↑ Wobst, Reinhard (2001). Cryptology Unlocked. Wiley. p. 20. ISBN 978-0-470-06064-3.↑ Kahn, David (1967). The Codebreakers. ISBN 978-0-684-83130-5). {{cite book}}: Check |isbn= value: invalid character (help)↑ Leyden, John (2006-04-19). "Mafia boss undone by clumsy crypto". The Register. සම්ප්‍රවේශය 2008-06-13. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)↑ "BA jihadist relied on Jesus-era encryption". The Register. 2011-03-22. සම්ප්‍රවේශය 2011-04-01. {{cite news}}: Italic or bold markup not allowed in: |publisher= (help)↑ Beutelspacher, Albrecht (1994). Cryptology. Mathematical Association of America. pp. 9–11. ISBN 0-88385-504-6.↑ Beutelspacher, Albrecht (1994). Cryptology. Mathematical Association of America. pp. 8–