M. M.Fadzli and W. A. Wan Mohamed, “Development of Nitrate-Nitrogen Calibration Curve Using Laboratory Resistivity Method in Acidic pH Condition”, rtcebe, vol. 4, no. 1, pp. 326–330, May 2023, Accessed: Jul. 25, 2026. [Online]. Available: https://penerbit.uthm.edu.my/periodicals/index.php/rtcebe/article/view/5729