(1973). Geologic sections, Jackson Purchase region, Kentucky, and adjacent areas. Washington, D C : Department of the Interior.
Chicago-referens (17:e uppl.)Geologic Sections, Jackson Purchase Region, Kentucky, and Adjacent Areas. Washington, D C : Department of the Interior, 1973.
MLA-referens (9:e uppl.)Geologic Sections, Jackson Purchase Region, Kentucky, and Adjacent Areas. Washington, D C : Department of the Interior, 1973.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.