Monge-Nájera, J., González, M. I., Rivas Rossi, M., & Méndez, V. H. (2002). A new method to assess air pollution using lichens as bioindicators. Revista De Biología Tropical, 50(1), 321–325. Retrieved from https://revistas.ucr.ac.cr/index.php/rbt/article/view/16290