Não informado. (2014). Geological Survey Professional Paper. U.S. Geological Survey Professional Paper.
Chicago-referens (17:e uppl.)Não informado. Geological Survey Professional Paper. Washington: U.S. Geological Survey Professional Paper, 2014.
MLA-referens (8:e uppl.)Não informado. Geological Survey Professional Paper. U.S. Geological Survey Professional Paper, 2014.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.