“Study of Mineralogical Variability of Ferruginous Quartzites of Productive Strata of the Eastern Wing of the Petrovsky Synclinal Fold With Using Diagram Mm-Mo”. Visnyk of V. N. Karazin Kharkiv National University. Series Geology. Geography. Ecology, no. 50, July 2019, pp. 54-62, https://doi.org/10.26565/2410-7360-2019-50-04.