Li Feng,  Computing Center Conditions for Non-analytic Vector Fields with Constant Angular Speed.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    December 2011, vol. 60(12). 2032 - 2034
    [viewed 25 April 2024]. Available from: https://publications.waset.org/pdf/7301.