2019. 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. 50 (Jul. 2019), 54–62. DOI:https://doi.org/10.26565/2410-7360-2019-50-04.