WASET
    Zelalem Teshome Wale,  I-Vague Normal Groups.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    December 2011, vol. 60(12). 1932 - 1936
    [viewed 27 April 2024]. Available from: https://publications.waset.org/pdf/9980.