Raafat, Safanah, Shibly Al-Samarraie, and Ali Mahmood. “Unity Sliding Mode Controller Design for Active Magnetic Bearings System”. Journal of Engineering 21, no. 6 (June 1, 2015): 90-107. Accessed November 29, 2019. http://joe.uobaghdad.edu.iq/index.php/main/article/view/416.