1. Visual cryptography;Naor,1995
2. Visual cryptography for general access structures;Ateniese;Inf. Comput.,1996
3. D.R. Stinson, An introduction to visual cryptography, Presented at Public Key Solutions ’97, Toronto, Canada, April 28–30, 1997.
4. Constructions and properties of k out of n visual secret sharing schemes;Verheul;Des. Codes Cryptogr.,1997
5. C. Blundo, A. De Santis, D.R. Stinson, On the contrast in visual cryptography schemes. J. Cryptology 12 (1999) 261–289.