Widayat, A. H., Anggayana, K., Indriati, T., Al Hakim, A. Y., Dwiantoro, M., Furqany, M., & Rifaldi, M. D. (2021). The Occurrence and Genesis of Silicified Coals in Tanjung Redeb, Embalut, and Loa Kulu, East Kalimantan, Indonesia. Indonesian Journal on Geoscience, 9(1), 27–43. https://doi.org/10.17014/ijog.9.1.27-43