R. Singh, R. Kaur, K. Lal, K. Rosin, M. Srivastava, and A. Shukla, “Optimization of Chromium(VI) and Copper(II) Adsorption on Chemically Treated Sawdust Using Response Surface Methodology”, ajc, vol. 29, no. 4, pp. 728–734, Jan. 2017.