Muhammad T. Alam and  Zheng Da Wu,  Admission Control Approaches in the IMS Presence Service.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2008, vol. 15(3). 943 - 958
    [viewed 25 April 2024]. Available from: https://publications.waset.org/pdf/3894.