1. The Memoria Technica Cipher;Abeles;Cryptologia,2003
2. The Mathematical Pamphlets of Charles Lutwidge Dodgson and Related Pieces;Abeles,1994
3. Some Victorian periodic polyalphabetic ciphers;Abeles,1998
4. F. Beaufort, Cryptography. A System of Secret Writing by the late Admiral Sir Francis Beaufort, K.C.B., adapted for telegrams and postcards (Card), London, Edward Sanford, n.d
5. C.L. Dodgson, Packet 60, items 1, 2, 3. The Mathematical Manuscripts of Charles Lutwidge Dodgson, Morris L. Parrish Collection, Department of Rare Books and Special Collections, Princeton University Library, Princeton, NJ