RDZANEK, Wojciech P., et al. “The Acoustic Impedance of a Vibrating Annular Piston Located on a Flat Rigid Baffle Around a Semi-Infinite Circular Rigid Cylinder”. Archives of Acoustics, vol. 37, no. 4, Oct. 2013, pp. 411–422, https://acoustics3.ippt.pan.pl/index.php/aa/article/view/70.