Não informado. (2001). Annual report of the United States Geological Survey. U.S. Geological Survey.
Lua i Stíl Chicago (17ú heag.)Não informado. Annual Report of the United States Geological Survey. Washington: U.S. Geological Survey, 2001.
Lua MLA (8ú heag.)Não informado. Annual Report of the United States Geological Survey. U.S. Geological Survey, 2001.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.