Sudnitsina, Diana, and Anna Cherevichko. “Estimation of River Utroya Ecological State in Intensive Organic Pollution Area Using Plankton Communities ’ Characteristics (Pskov Region)”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (August 9, 2015): 62–64. Accessed April 28, 2024. https://journals.rta.lv/index.php/ETR/article/view/882.