Siswanto, W. . Mindari, S. B. . Santoso, and R. D. . Rahayu, “Effectiveness of Ameliorant Humic Acid and Silica Based on Availability of Sandy Soil Nitrogen for Rice”, Nusantara Sci. Tech. Proc., vol. 2022, no. 24, pp. 340–343, Jun. 2022, doi: 10.11594/nstp.2022.2467.