Jian Tang,  On Completely Semiprime, Semiprime and Prime Fuzzy Ideals in Ordered Semigroups.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    March 2011, vol. 51(3). 360 - 365
    [viewed 07 May 2024]. Available from: https://publications.waset.org/pdf/15343.