Rudnev, V. V., and M. V. Kumani. “Dynamics of Changes in Saprobity of Water Bodies of the Kursk Region”. Proceedings of Voronezh State University. Series: Geography. Geoecology, no. 1, Mar. 2023, pp. 122-34, doi:10.17308/geo/1609-0683/2023/1/122-134.