Mahat, Hanifah, et al. “Kajian Tahap Amalan Kelestarian Dalam Kalangan Murid Prasekolah Kementerian Pendidikan Malaysia Daerah Hulu Langat, Selangor: A Study on the Level of Sustainability Practices Among Ministry of Education Preschool Pupils in Hulu Langat, Selangor”. GEOGRAFI, vol. 3, no. 1, Apr. 2015, pp. 25-34, https://ejournal.upsi.edu.my/index.php/GEOG/article/view/1845.