D.Elleuch and  T.Damak,  Adaptive Sliding Mode Observer for a Class of Systems.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    August 2010, vol. 44(8). 743 - 749
    [viewed 26 May 2022]. Available from: https://publications.waset.org/pdf/9018.