Hamid Reza Boveiri,  Persian Printed Numerals Classification Using Extended Moment Invariants.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2010, vol. 39(3). 384 - 391
    [viewed 28 October 2021]. Available from: https://publications.waset.org/pdf/13920.