Abdul Rahim, Marham, and Emedya Murniwaty Samsudin. “Sound Absorption Performance of Ink-Tube Waste As Absorber”. Recent Trends in Civil Engineering and Built Environment, vol. 2, no. 1, May 2021, pp. 87-93, https://periodical.uthm.edu.my/index.php/rtcebe/article/view/1313.