Findik, Serap. “Adsorption of Diazo Dye Direct Red-28 and Tetra-Azo Dye Direct Black-22 Using Calcined Kaolin in Aqueous Solutions”. Bulletin of the Chemical Society of Ethiopia 37, no. 3 (March 6, 2023): 593–610. Accessed November 10, 2026. https://www.ajol.info/index.php/bcse/article/view/242898.