Systems. Laguna Hills, CA: Aegean Park Press, 1992. General Solution of the ADFGVX Cipher System, J. Rives Childs, Aegean Park Press, ISBN 0-89412-284-3
Gaines, Cryptanalysis, a study of ciphers and their solution, Dover, 1956, ISBN 0-486-20097-3 American Cryptogram Association - Railfence cipher online