Posa, A., P. Oresta, and A. Lippolis. “INFLUENCE OF THE SPOOL VELOCITY ON THE PERFORMANCE OF A DIRECTIONAL HYDRAULIC VALVE”. International Journal of Fluid Power, vol. 14, no. 3, Dec. 2018, pp. 15-25, https://journals.riverpublishers.com/index.php/IJFP/article/view/213.