See, Koh Liew, et al. “Kajian Perbandingan Antara Realiti Dengan Persepsi Mengenai Kualiti Bekalan Air Di Kelantan: Comparison Between Reality and Perception of Water Supply Quality in Kelantan”. GEOGRAFI, vol. 3, no. 1, Apr. 2015, pp. 35-47, https://ejournal.upsi.edu.my/index.php/GEOG/article/view/1846.