Che Ngah, M. S. Y., Y. Saleh, M. Hashim, N. Nayan, and H. Ibrahim. “Penggunaan Sumber Air Bersih DalamPerkhidmatan Mencuci Kereta Di Tanjong Malim,Perak Dan Hulu Bernam, Selangor: Clean Water Usage in Car Wash Services in Tanjong Malim,Perak and Hulu Bernam, Selangor”. Perspektif Jurnal Sains Sosial Dan Kemanusiaan, vol. 3, no. 2, Nov. 2011, pp. 75-85, https://ejournal.upsi.edu.my/index.php/PERS/article/view/1601.