1. Techniques for data hiding
2. R. E. Ziemer and R. L. Peterson. “Digital Communications and Spread Spectrum System,” pp. 327–357, Macmillan, New York (1985).
3. I. J. Cox, J. Kilian, T. Leighton, and T. Shamoon, “Secure spread spectrum watermarking for multimedia,” NEC Technical Report 95-10, NEC Research Institute (1995).