Zhu, Y., and E. J. Barth. “ACCURATE SUB-MILLIMETER SERVO-PNEUMATIC TRACKING USING MODEL REFERENCE ADAPTIVE CONTROL (MRAC)”. International Journal of Fluid Power, vol. 11, no. 2, Aug. 2010, pp. 43-55, https://journals.riverpublishers.com/index.php/IJFP/article/view/484.