Tham Cheong Sheng, Mariah Awang, and Mohammad Ashraf Abdul Rahman. “Preliminary Study of Energy and Cost Saving Potential of Lighting System in Teaching Building”. Politeknik & Kolej Komuniti Journal of Social Sciences and Humanities, vol. 1, no. 1, Nov. 2017, pp. 160-6, https://app.mypolycc.edu.my/journal/index.php/PMJSSH/article/view/139.