Yanling Zhu and  Kai Wang,  Positive Periodic Solutions for a Predator-prey Model with Modified Leslie-Gower Holling-type II Schemes and a Deviating Argument.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    August 2012, vol. 68(8). 999 - 1002
    [viewed 25 May 2020]. Available from: https://publications.waset.org/pdf/6973.