Shaoquan Sun and  Chunxiang Liu,  (λ, μ)-Intuitionistic Fuzzy Subgroups of Groups with Operators.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    September 2016, vol. 117(9). 456 - 462
    [viewed 11 May 2024]. Available from: https://publications.waset.org/pdf/10005726.