Sauti, M. S., E. A. Azman, R. Ismail, C. L. Phooi, and S. Lakulassa. “Effects Of Blue Npk Fertilizer And/Or Biochar On The Growth And Yield Of Okra (Abelmoschus Esculentus L.) Plant Using Silabukan Soil”. Jurnal Penelitian Pertanian Terapan, vol. 24, no. 2, June 2024, pp. 231-44, doi:10.25181/jppt.v24i2.2783.