Marabyan, Sh.L., et al. “STUDY OF CONTENT OF Cr, As, Cd, Pb ELEMENTS IN SOME RIVERS OF ARMENIA”. Proceedings of the YSU B: Chemical and Biological Sciences, vol. 48, no. 3 (235), Nov. 2014, pp. 51-54, doi:10.46991/PYSU:B/2014.48.3.051.