WASET
    Ola A. Younis and  Said Ghoul,  Systems Versioning: A Features-Based Meta-Modeling Approach.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    May 2014, vol. 90(6). 988 - 992
    [viewed 19 April 2024]. Available from: https://publications.waset.org/pdf/9998563.