Garba, Abdurrahman, et al. “Adsorption of Methylene Blue Using Activated Carbon Made from Watermelon Rinds”. Journal of Sustainable Materials Processing and Management , vol. 1, no. 1, Dec. 2021, pp. 38-43, https://penerbit.uthm.edu.my/ojs/index.php/jsmpm/article/view/9955.