WASET
    Lidia Obojska,  Relational Framework and its Applications.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    December 2011, vol. 60(12). 1954 - 1959
    [viewed 08 May 2024]. Available from: https://publications.waset.org/pdf/15795.