WASET
    Abdullah A. H. Alzahrani and  Majd Zohri Yafi and  Fawaz K. Alarfaj,  Some Considerations on UML Class Diagram Formalisation Approaches .   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    April 2014, vol. 89(5). 741 - 744
    [viewed 24 April 2024]. Available from: https://publications.waset.org/pdf/9998151.