Hongbo Guo. “Robust QFT-Based Position Control of an Asymmetric Hydraulic Cylinder Electro-Hydraulic Servo System”. International Journal of Robotics and Automation Technology 5 (August 10, 2018):  1–6. Accessed May 15, 2024. https://zealpress.com/jms/index.php/ijrat/article/view/236.