Nuryenti, Ismi, Dwi Probowati Sulistyani, and Siti Masreah Bernas. “Kandungan Hara N, P, K Pada Gawangan Dan Jalan Panen Perkebunan Kelapa Sawit”. Jurnal Lahan Suboptimal : Journal of Suboptimal Lands 5, no. 2 (March 22, 2018): 219–224. Accessed September 27, 2021. https://jlsuboptimal.unsri.ac.id/index.php/jlso/article/view/180.