Shukla, A., and D. F. Thompson. “AN INVESTIGATION OF THE EFFECT OF FEEDBACK CONTROL ON THE BIFURCATION STABILITY OF A NONLINEAR SERVOHYDRAULIC SYSTEM”. International Journal of Fluid Power, vol. 6, no. 2, Aug. 2005, pp. 37-46, https://journals.riverpublishers.com/index.php/IJFP/article/view/570.