N. L. S. Ngadiman, “Preliminary Study of pH Sensor for Engine Oil Deterioration Detection Using Anodized Ta2O5 Nanotubular”, IJIE, vol. 14, no. 3, pp. 229–240, Jun. 2022, Accessed: Aug. 07, 2026. [Online]. Available: https://journal.uthm.edu.my/index.php/ijie/article/view/10403