Books:

Budiansky, Stephen. Battle of Wits. London: The Free Press, 2000.

Calvocoressi, Peter. Top Secret Ultra. London: Cassel Ltd. 1980.

Freedman, Maurice. Unravelling Enigma – Winning the Code War at Station X. Great Britain: Leo Cooper, 2000.

Harper, Stephen. Capturing Enigma. Great Britain: Sutton Publishing, 1999.

Sebag-Montefiore. Enigma – The Battle for the Code. London: Weidenfeld & Nicolson.

Online:

Enigma Cipher Machines, Fialka, Nema, other Cipher Machines, Antique Computers and Calculators
http://w1tp.com/enigma/

The Enigma Cipher Machine
http://www.codesandciphers.org.uk/enigma/

Technical Details of the Enigma
http://users.telenet.be/d.rijmenants/en/enigmatech.htm

The Computer Era
http://fn2.freenet.edmonton.ab.ca/~jsavard/crypto/comp04.htm

Code Books
http://fn2.freenet.edmonton.ab.ca/~jsavard/crypto/pp0104.htm

Introduction To Codes, Ciphers, & Codebreaking
http://www.vectorsite.net/ttcode1.html#m1

Bletchley Park
http://www.bletchleypark.org.uk/page.cfm?pageid=264

Bletchley Park.net
http://www.bletchleypark.net/algorithms/

The Secret Language
http://www.exploratorium.edu/ronh/secret/secret.html

The Bletchley Park Trust
http://www.bletchleypark.org.uk/

The American Cryptogram Association
http://www.cryptogram.org/

National Cryptologic Museum
http://www.nsa.gov/museum/

The Cryptography FAQ
http://www.faqs.org/faqs/cryptography-faq/part01/

Alan Turing - Home Page
http://www.turing.org.uk/turing/index.html

MAW 97 Ciphers: The Enigma Machine
http://www.math.arizona.edu/~dsl/enigma.htm

---

Enigma Cipher Machine Homepage: Jamie Brownell