1. David Kahn, The Codebreakers, Macmillan Publishing, 1967
2. netcom.com,/pub/qwerty, FTP site for reviewed image based steganographic software
3. E. Koch, J. Zhao, Embedding Robust Labels into Images for Copyright Protection, Proc. of the International Congress on Intellectual Property Rights for Specialized Information, Vienna, Austria, Aug 1995
4. J. Brassil, S.Low, N. Maxemchuk, Electronic Marking and Identification Techniques to Discourage Document Copying, AT&T Bell Labs, Murray Hill, NJ
5. E. Koch, J. Rindfrey, J. Zhao, Copyright Protection for Multimedia Data, Proceedings of the International Conference on Digital Media and Electronic Publishing, Dec 1994, Leeds UK