Ekpete, O. A., F. Kpee, J. C. Amadi, and R. B. Rotimi. “Adsorption of Chromium(VI) and Zinc(II) Ions on the Skin of Orange Peels (<i>Citrus sinensis</I>)”. Journal of Nepal Chemical Society, vol. 26, Aug. 2010, pp. 31-39, doi:10.3126/jncs.v26i0.3628.