Gang Liu and  Huimin Song and  Can Wang and  Runnan Zhang and  Lu Fang,  An Attribute Based Access Control Model with POL Module for Dynamically Granting and Revoking Authorizations.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    May 2017, vol. 126(6). 758 - 764
    [viewed 01 June 2020]. Available from: https://publications.waset.org/pdf/10007354.