Xin Xu Martin Tomlinson Marcel Ambroze Mohammed Ahmed Biorthogonal matrix dirty paper coding for information hiding in still images. 454-459 2007 ICDIM http://dx.doi.org/10.1109/ICDIM.2007.4444265 conf/icdim/2007 db/conf/icdim/icdim2007.html#XuTAA07