PAJEWSKI, W., P. KIEŁCZYŃSKI, and M. SZALEWSKI. “Radiation of Piezoelectric Rings into the Air through Cylindrical Waveguides”. Archives of Acoustics 20, no. 4 (December 31, 1995): 361–372. Accessed March 4, 2026. https://acoustics.ippt.gov.pl/index.php/aa/article/view/1276.