“Preparation and Characterization of P-Sulfonated Calix[4]arene Functionalized Chitosan Hydrogel Beads and Their Preliminary Adsorption Study towards Removal of Lead(II) and Zinc(II) Ions”. Malaysian Journal of Fundamental and Applied Sciences 16, no. 4 (August 17, 2020): 429–432. Accessed September 16, 2026. https://mjfas.utm.my/index.php/mjfas/article/view/1765.