Thi T. Nguyen and  Lee N. Gordon-Brown,  Fuzzy Numbers and MCDM Methods for Portfolio Optimization.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    December 2012, vol. 72(12). 1593 - 1605
    [viewed 28 October 2021]. Available from: https://publications.waset.org/pdf/7716.