Sutarta, Edy Sigit, Dhimas Wiratmoko, and Erwin Nyak Akoeb. “Soil Fertility, Oil Palm Growth and Productivity on Three Pyritic Depths”. Jurnal Penelitian Kelapa Sawit 28, no. 2 (August 1, 2020): 71-84. Accessed January 19, 2026. http://jurnalkelapasawit.iopri.org/index.php/jpks/article/view/104.