A. N. K. Nasir and  R. M. T. Raja Ismail and  M. A. Ahmad,  Performance Comparison between Sliding Mode Control (SMC) and PD-PID Controllers for a Nonlinear Inverted Pendulum System.   journal   = {International Journal of Electrical and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    October 2010, vol. 46(10). 1508 - 1513
    [viewed 27 January 2020]. Available from: https://publications.waset.org/pdf/1558.