Li Feng,  Ten Limit Cycles in a Quintic Lyapunov System.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    December 2011, vol. 60(12). 1951 - 1953
    [viewed 11 May 2024]. Available from: https://publications.waset.org/pdf/8747.