Ryan, J.G., E.A.G. Shaw, A.J. Brammer, and G. Zhang. “ENCLOSURE FOR LOW-FREQUENCY ASSESSMENT OF ACTIVE NOISE REDUCING CIRCUMAURAL HEADSETS AND HEARING PROTECTORS”. Canadian Acoustics 21, no. 4 (December 1, 1993): 19–20. Accessed April 20, 2024. https://jcaa.caa-aca.ca/index.php/jcaa/article/view/820.