1. P. Ochirbat et al., Coal Industries of Mongolia in the Twentieth Century (Ulaanbaatar, 2002).
2. P. Zuzaan et al., “Some results of a study to determine coal quality and elements contents,” in Proc. of the 3rd Intern. School on Contemporary Physics (ISCP-3) (Ulaanbaatar, 2005), pp. 100–103.
3. P. Zuzaan et al., “X-Ray fluorescence technique for determination of elemental contents in Shivee-Ovoo and Baganuur Coal Mines of Mongolia,” Phys. Sci. J. Nat. Univ. Mongolia, Ulaanbaatar, No. 225(12), 55–57 (2005).
4. E. Kowalska and P. Urbanski, “Measurements of Ash content in lignite from Mongolian Mines,” Annu. Rep., 2003 (Inst. of Nucl. Chemistry and Technology, Warszawa, 2004), pp. 128–129.
5. E. Kowalska et al., “A new XRF analyser AF-30,” Ibid., 129–130.