Hakim S, Abd. “Synthesis and Characterization of PVA-Enzyme GA PPy PVC-KTpClPB-O-NPOE Indicator Electrodes, XRD Analysis, FTIR and Variable Signal Analysis”. Jurnal Penelitian Pendidikan IPA, vol. 9, no. 3, Mar. 2023, pp. 1149-54, doi:10.29303/jppipa.v9i3.2389.