Dangjun Zhao and  Yongji Wang and  Lei Liu,  GPI Observer-based Tracking Control and Synchronization of Chaotic Systems.   journal   = {International Journal of Electrical and Computer Engineering}, [online]. World Academy of Science, Engineering and Technology.
    August 2011, vol. 56(8). 815 - 818
    [viewed 05 August 2020]. Available from: https://publications.waset.org/pdf/15075.