H., H., Mindari, W., & Priyadarshini, R. (2024). Characterization of Humic Acid Using E4/E6 Ratio in Various Land Uses in Jatiarjo Village, Prigen District, Pasuruan. Engineering And Technology Journal, 9(6), 4179–4185. https://doi.org/10.47191/etj/v9i06.01