WASET
    P. Ghann and  J. Shiguang and  C. Zhou,  Component Lifecycle and Concurrency Model in Usage Control (UCON) System.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    October 2014, vol. 87(3). 531 - 538
    [viewed 25 April 2024]. Available from: https://publications.waset.org/pdf/9999650.