Ahmadian, M., N. Yosefi, A. Toolabi, N. Khanjani, S. Rahimi, and A. Fatehizadeh. 2012. “Adsorption of Direct Yellow 9 and Acid Orange 7 from Aqueous Solutions by Modified Pumice”. Asian Journal of Chemistry 24 (7):3094-98. https://asianpubs.org/index.php/ajchem/article/view/9302.