S. Subarudi, H. Kartodihardjo, S. Soedomo, H. Sapardi, and M. Z. Muttaqin, “Analysing Policy Formulation for Coal Mining Activities within State Forest Zone in Indonesia: A case study of East Kalimantan Province”, IJSBAR, vol. 26, no. 1, pp. 314–330, Apr. 2016.