Rochdi Omami and  Mohamed Omami and  Raouf Ouni,  Group of p-th Roots of Unity Modulo n.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    July 2010, vol. 43(7). 979 - 990
    [viewed 11 May 2021]. Available from: https://publications.waset.org/pdf/10881.