Hironori Karachi and  Haruka Yamashita,  Attribute Analysis of Quick Response Code Payment Users Using Discriminant Non-negative Matrix Factorization.   journal   = {International Journal of Economics and Management Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2021, vol. 172(4). 401 - 405
    [viewed 02 May 2024]. Available from: https://publications.waset.org/pdf/10011957.