WASET
    M. Kamel El-Sayed,  Similarity Based Membership of Elements to Uncertain Concept in Information System.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    February 2018, vol. 135(3). 62 - 65
    [viewed 29 March 2024]. Available from: https://publications.waset.org/pdf/10008697.