Fatimah Almah Saaid and  Darfiana Nur and  Robert King,  SDVAR Algorithm for Detecting Fraud in Telecommunications.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    May 2012, vol. 65(5). 549 - 555
    [viewed 31 March 2020]. Available from: https://publications.waset.org/pdf/8767.