Hussain, A., N. L. Hashim, and S. S. Nathan. “Development of Hearing-Impaired Evaluation Model for Mobile Phone”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 10, no. 1-11, Feb. 2018, pp. 59-62, https://jtec.utem.edu.my/jtec/article/view/3850.