Labiba Gilani and  Asifullah Khan and  Anwar M. Mirza,  Distortion Estimation in Digital Image Watermarking using Genetic Programming.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2008, vol. 15(3). 839 - 844
    [viewed 06 December 2019]. Available from: https://publications.waset.org/pdf/2365.