John Muir Institute for Environmental Studies and University of New Mexico. (1979). Environmental Ethics. Environmental Philosophy.
Lua i Stíl Chicago (17ú heag.)John Muir Institute for Environmental Studies and University of New Mexico. Environmental Ethics. Denton, Tex: Environmental Philosophy, 1979.
Lua MLA (8ú heag.)John Muir Institute for Environmental Studies and University of New Mexico. Environmental Ethics. Environmental Philosophy, 1979.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.