Results of tests of pH meters, concentration of sulfide ions and lead ions of the hydrochemical probe 04.05.202015.11.2003 by Светлана Малахатко V. I. Zaburdaev, I. G. Kiryushchenko, P. V. Gai, A. V. Nikitin, J. M. Danilenko, E. I. Oats Full text in PDF(RUS)