G. O. El-Sayed, H. A. Dessouki, H. S. Jahin, and S. S. Ibrahiem. “Photocatalytic Degradation of Tetracycline in Aqueous Solutions by Kaolin Nanoparticles”. World Journal of Pharmaceutical Sciences, vol. 3, no. 4, Apr. 2015, pp. 779-86, https://wjpsonline.com/index.php/wjps/article/view/photocatalytic-degradation-tetracycline-kaolin-nanoparticles.