* Władysław Kozaczuk, "Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two", edited and translated by Christopher Kasparek, University Publications of America, 1984, ISBN 978-0-89093-547-7.
* Władysław Kozaczuk, "Enigma: How the German Machine Cipher Was Broken, and How It Was Read by the Allies in World War Two", edited and translated by Christopher Kasparek, University Publications of America, 1984, ISBN 978-0-89093-547-7.