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Lua i Stíl Chicago (17ú heag.)Heacox, Kim. National Geographic the National Parks: An Illustrated History. Washington, D.C: National Geographic, 2016.
Lua MLA (9ú heag.)Heacox, Kim. National Geographic the National Parks: An Illustrated History. National Geographic, 2016.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.