S.E.G. Goh, R.A. Aziz, M. N. Salleh, et al. Calibration of Arduino Sensors for Soil Moisture Monitoring in Sandy Soils. IJIE. 2026;18(5):263-271. Accessed November 7, 2026. https://journal.uthm.edu.my/index.php/ijie/article/view/23276