NGADERMAN, T.; RELIUBUN, L.; DEGEI, I. Batubara Bituminous Menjadi Asam Humat Sebagai Inovasi Pendamping Pupuk, Besum Papua. Jurnal Penelitian Ilmu Pendidikan Indonesia, [S. l.], v. 4, n. 3, p. 1927–1937, 2025. DOI: 10.31004/jpion.v4i3.668. Disponível em: https://jpion.org/jpion.org/index.php/jpi/article/view/668. Acesso em: 3 jul. 2026.