Khair, F. A. ., A. . Putra, M. J. . M. Nor, and . M. . Selamat. “Analysis of Sound Absorption of Hollow Tube Absorbers”. International Journal of Automotive and Mechanical Engineering, vol. 13, no. 2, Dec. 2022, pp. 3492-0, doi:10.15282/ijame.13.2.2016.16.0288.