Kela, L., and P. Vähäoja. “CONTROL OF AN ADJUSTABLE HELMHOLTZ RESONATOR IN A LOW-PRESSURE HYDRAULIC SYSTEM”. International Journal of Fluid Power, vol. 10, no. 3, Nov. 2009, pp. 29-39, https://journals.riverpublishers.com/index.php/IJFP/article/view/493.