Sofyan T, Wilogo AZ, Saputra AY, Irjantoko R, Misdiyanta P, Trianda O. A Comparative Study of Coal Quality: Insights from Actual and Proximate Analysis Models. int. j. hydrol. environ. sustain. [Internet]. 2026 Jan. 11 [cited 2026 Jan. 16];4(1):23-31. Available from: https://journal.foundae.com/index.php/ijhes/article/view/538