Não informado. (1883). Bulletin of the United States Geological Survey. U.S. Department of the Interior.
Chicago-referens (17:e uppl.)Não informado. Bulletin of the United States Geological Survey. Washington: U.S. Department of the Interior, 1883.
MLA-referens (8:e uppl.)Não informado. Bulletin of the United States Geological Survey. U.S. Department of the Interior, 1883.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.