Bolortamir, T., H. Habaki, and R. Egashira. “Effect of Modification of Mongolian Natural Zeolites on Adsorption of Chromium from Aqueous Solution”. Proceedings of the Mongolian Academy of Sciences, vol. 49, no. 4, Mar. 2011, pp. 71-77, doi:10.5564/pmas.v0i4.49.