Norsinnira Zainul Azlan and  Hiroshi Yamaura,  Adaptive Impedance Control for Unknown Non-Flat Environment.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    February 2013, vol. 74(2). 191 - 196
    [viewed 09 May 2021]. Available from: https://publications.waset.org/pdf/5819.