Não informado. Outdoor Recreation Research. U.S. Department of the Interior, Bureau of Outdoor Recreation.
Lua i Stíl Chicago (17ú heag.)Não informado. Outdoor Recreation Research. Washington: U.S. Department of the Interior, Bureau of Outdoor Recreation.
Lua MLA (8ú heag.)Não informado. Outdoor Recreation Research. U.S. Department of the Interior, Bureau of Outdoor Recreation.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.