T.G. Krupnova, I.V. Mashkova and A.M. Kostryukova (2017) “USING BIRCH LEAVES TO INDICATE AIR POLLUTION”, GEOMATE Journal, 13(40), pp. 54–59. Available at: https://geomatejournal.com/geomate/article/view/1368 (Accessed: 29 March 2024).