Aziza, Humairo, et al. “Analisis Efisiensi Penggunaan Pupuk NPK, Janjang Kosong Kelapa Sawit Dan Limbah Cair Terhadap Hasil Produksi Tanaman Kelapa Sawit: Analysis of Efficiency of Using NPK Fertilizer, Empty Palm Oil Bunches and Liquid Waste on Oil Palm Production”. Buletin Loupe, vol. 19, no. 02, Dec. 2023, pp. 147-55, doi:10.51967/buletinloupe.v19i02.2914.