Lua APA (7ú heag.)
Tweed, W. C. (2010). Uncertain path: A search for the future of national parks. University of California Press.
Lua i Stíl Chicago (17ú heag.)
Tweed, William C. Uncertain Path: A Search for the Future of National Parks. Berkeley: University of California Press, 2010.
Lua MLA (9ú heag.)
Tweed, William C. Uncertain Path: A Search for the Future of National Parks. University of California Press, 2010.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.