Fatmawati, Zulaikhah, et al. “Adsorptive Removal of Chemical Oxygen Demand Using Eggshells and Tea Waste Entrapped in Calcium Alginate”. Journal of Tropical Pharmacy and Chemistry, vol. 7, no. 2, Dec. 2023, pp. 67-77, doi:10.25026/jtpc.v7i2.480.