КРАЙНЮКОВ, О. М. “ESTIMATION OF THE ECOLOGY-TOXICOLOGICAL STATE OF RIVER LOPAN WITHIN THE LIMITS OF KHARKIV”. Visnyk of V. N. Karazin Kharkiv National University. Series Еcоlogy, no. 1147, 1, pp. 57-62, https://periodicals.karazin.ua/ecology/article/view/3921.