KOZŁOWSKI, Emil, and Rafał MŁYŃSKI. “Measurement of Earmuffs Attenuation at High Audible Frequencies”. Archives of Acoustics 42, no. 2 (June 30, 2017): 249–254. Accessed March 4, 2026. https://acoustics.ippt.gov.pl/index.php/aa/article/view/1738.