Lihong Ma Dong Yu Hanqing Lu Adaptive Spread-Transform Dither Modulation for Color Image Watermarking. 2164-2168 2008 GLOBECOM http://dx.doi.org/10.1109/GLOCOM.2008.ECP.417 conf/globecom/2008 db/conf/globecom/globecom2008.html#MaYL08