Template:Culberson, 1973a
- Culberson, W.L. 1973. The Parmelia perforata Group: Niche Characteristics of Chemical Races, Speciation by Parallel Evolution, and a New Taxonomy. The Bryologist 76(1): 20–29. RLL List # 85 / Rec.# 3858 – Recent Literature on Lichens DOI: 10.2307/3241229