Analisis Mutu Batubara sebagai Bahan Bakar Berdasarkan Karakteristik Abu, Densitas Relatif dan Logam Berat. Jurnal Serambi Engineering, [S. l.], v. 11, n. 2, 2026. Disponível em: http://jse.serambimekkah.id/index.php/jse/article/view/1733. Acesso em: 12 may. 2026.