Bormann, F. H., & Kellert, S. R. (1991). Ecology, economics, ethics: The broken circle. Yale University Press.
Lua i Stíl Chicago (17ú heag.)Bormann, F. Herbert, agus Stephen R. Kellert. Ecology, Economics, Ethics: The Broken Circle. New Haven: Yale University Press, 1991.
Lua MLA (9ú heag.)Bormann, F. Herbert, agus Stephen R. Kellert. Ecology, Economics, Ethics: The Broken Circle. Yale University Press, 1991.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.