Istomina, N. B., and O. V. Likhacheva. “Lichens As Indicators of the Urban Environment Quality”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (August 9, 2015): 20–21. Accessed May 1, 2024. https://journals.ru.lv/index.php/ETR/article/view/872.