Nurmi, J., and J. Mattila. “DETECTION AND ISOLATION OF LEAKAGE AND VALVE FAULTS IN HYDRAULIC SYSTEMS IN VARYING LOADING CONDITIONS, PART 2: FAULT DETECTION AND ISOLATION SCHEME”. International Journal of Fluid Power, vol. 13, no. 1, Mar. 2012, pp. 17-27, https://journals.riverpublishers.com/index.php/IJFP/article/view/694.