United States National Herbarium - Smithsonian (US:Lichens) - Collector: H. Willey
Number: s.n. Date: 1874-00-00 Verbatim Date: 1874 Locality: United States, New Hampshire, Dixville. - CC BY-NC 3.0 - Source: Consortium of Lichen Herbaria (2023) http//:lichenportal.org/portal/index.php. Accessed on December 14.
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
