P. P. Kesumah, S. S. Amin, J. Wiratama, and B. . Adhitya, “Identification of Coal Distribution Pattern Using Well Logging Method Based on Gamma Ray Log Data and Log Density in Area X PT PMC Site Sungai Lilin: Identification of coal distribution pattern”, Jur. Bio-Geo. Mat. E, vol. 3, no. 2, pp. 47-59, Sep. 2023.