Kavala Kiran Kumar and  R. Govardhana Rao,  Fuzzy Tuned PID Controller with D-Q-O Reference Frame Technique Based Active Power Filter.   journal   = {International Journal of Electrical and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2014, vol. 87(3). 647 - 653
    [viewed 18 October 2019]. Available from: https://publications.waset.org/pdf/9998653.