1. R.G. van Schyndel, A.Z. Tirkel, C.F. Osborne, A digital watermark, in: Proc. 1st International Conference on Image Processing, 2, 1994, 86–90, vol. 2.
2. R.B. Wolfgang, E.J. Delp, A watermark for digital images, in: Proc. 3rd IEEE International Conference on Image Processing, 3, 1996, 219–222, vol. 3.
3. Hidden digital watermarks in images;Hsu;IEEE Trans. Image Process.,1999
4. Digital watermarking of still images with gray-level digital watermarks;Niu;IEEE Trans. Consum. Electron.,2000
5. H. Liu, M. Steinebach, Digital watermarking for image authentication with localization, in: Proc. International Conference on Image Processing, 2006, 1973–1976.