Ts, B., K. B, O. G, V. I. E, S. E. V, T. D, and K. A. T. “BACKGROUND CONCENTRATION OF MICROELEMENTS IN ULAANBAATAR REGIONAL NATURAL SURFACE SOIL”. Proceedings of the Mongolian Academy of Sciences, vol. 58, no. 2, Sept. 2018, pp. 15-24, doi:10.5564/pmas.v58i2.1001.