TROCHIDIS, A., and G. PAPANIKOLAOU. “The Use of Helmholtz Resonators and Panel Absorbers in the Design of Duct Silencers”. Archives of Acoustics, vol. 18, no. 3, May 2014, pp. 435-46, https://acoustics3.ippt.pan.pl/index.php/aa/article/view/1154.