Shaohui Liu Hongxun Yao Wen Gao Yongliang Liu An image fragile watermark scheme based on chaotic image pattern and pixel-pairs. 869-882 2007 185 Applied Mathematics and Computation 2 http://dx.doi.org/10.1016/j.amc.2006.07.036 db/journals/amc/amc185.html#LiuYGL07