Arisanti, R., M. Yusuf, and M. Faizal. “Study of The Effect of Coal Quality Parameters on Gas Methane (CH4) Emission in Coal Fire for Sustainable Environment”. Indonesian Journal of Environmental Management and Sustainability, vol. 1, no. 1, Nov. 2017, pp. 19-22, doi:10.26554/ijems.2017.1.1.19-22.