WASET
    Ling Liu and  Yuan Ye,  Existence and Uniqueness of Periodic Solution for a Discrete-time SIR Epidemic Model with Time Delays and Impulses.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    September 2011, vol. 57(9). 1515 - 1521
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/15019.