Darrow, Robert A. (1950). "The arboreal lichen flora of southeastern Arizona". American Midland Naturalist. 43 (2): 484–502. doi:10.2307/2421916.
Krog, Hildur (1982). "Punctelia, a new lichen genus in the Parmeliaceae". Nordic Journal of Botany. 2 (3): 287–292. doi:10.1111/j.1756-1051.1982.tb01191.x.