M. A. Zulkefle, R. A. Rahman, M. Rusop, W. F. H. Abdullah, and S. H. Herman, “Porous TiO2 Thin Film for Egfet pH Sensing Application”, IJET, vol. 7, no. 4.42, pp. 112–114, Dec. 2018, doi: 10.14419/ijet.v7i4.42.25690.