Sofyan, T.; Wilogo, A. Z.; Saputra, A. Y.; Irjantoko, R.; Misdiyanta, P.; Trianda, O. A Comparative Study of Coal Quality: Insights from Actual and Proximate Analysis Models. int. j. hydrol. environ. sustain. 2026, 4 (1), 23-31. https://doi.org/10.58524/ijhes.v4i1.538.