Xianfeng Zhao Bingbing Xia Yi Deng Strengthening QIM-Based Watermarking by Non-uniform Discrete Cosine Transform. 309-324 2008 Information Hiding http://dx.doi.org/10.1007/978-3-540-88961-8_22 conf/ih/2008 db/conf/ih/ih2008.html#ZhaoXD08