Cunha, M. A. B., R. Guenther, E. R. De Pieri, and V. J. De Negri. “DESIGN OF CASCADE CONTROLLERS FOR A HYDRAULIC ACTUATOR”. International Journal of Fluid Power, vol. 3, no. 2, Aug. 2002, pp. 35-46, https://journals.riverpublishers.com/index.php/IJFP/article/view/624.