USDA & Economic research service. (2001). Agri-environment polisy at the crossroads: Guideposts on a changing landscape; agricultural economic report No794.
Lua i Stíl Chicago (17ú heag.)USDA agus Economic research service. Agri-environment Polisy at the Crossroads: Guideposts on a Changing Landscape; Agricultural Economic Report No794. 2001.
Lua MLA (9ú heag.)USDA agus Economic research service. Agri-environment Polisy at the Crossroads: Guideposts on a Changing Landscape; Agricultural Economic Report No794. 2001.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.