Znotiņa, Olita, and Rasma Trejakova. “AIR POLLUTION LEVELS DETERMINATION USING METHODS OF LICHENINDICATION IN TOWN PĻAVIŅAS”. HUMAN. ENVIRONMENT. TECHNOLOGIES. Proceedings of the Students International Scientific and Practical Conference, no. 20 (April 20, 2016): 349–354. Accessed December 5, 2024. https://journals.ru.lv/index.php/HET/article/view/3504.