Rutto, Hilary, et al. “Optimization of Ca2+ Removal from Cooling Tower Water Using Amberlite IR120 and Amberjet 1200 Resins: A Response Surface Methodology Study”. Asian Journal of Chemistry, vol. 35, no. 11, Oct. 2023, pp. 2739-48, doi:10.14233/ajchem.2023.30234.