A. Hartono, B. Nugroho, and F. K. Edwar, “Manufacture Potassium Silicate Fertilizer Based on Quartz Sand from Bangka ”, J. Il. Tan. Lingk., vol. 25, no. 1, pp. 19–24, Apr. 2023, doi: 10.29244/jitl.25.1.19-24.