Smithsonian Institution, National Museum of Natural History, Department of Botany – CC BY-SA-NC 3.0 http://collections.mnh.si.edu/search/botany/?irn=2871820
Redinger, K. (1938) Arthoniaceae, Graphidaceae . In Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. Band 9, 2 Abt., Part 1 (G. L. Rabenhorst, ed.): 181–404. Leipzig: Borntraeger
Smithsonian Institution, National Museum of Natural History, Department of Botany – CC BY-SA-NC 3.0 http://collections.mnh.si.edu/search/botany/?irn=2871820
