Insani, Munadia, et al. “Optimizing Anionic Polyacrylamide As Precipitating Agent for Effective Copper Ion Removal in Educational Laboratory Wastewater Treatment”. Jurnal Penelitian Pendidikan IPA, vol. 11, no. 3, Mar. 2025, pp. 1070-8, doi:10.29303/jppipa.v11i3.10546.