USDA & Economic research service. (2001). Agri-environment polisy at the crossroads: Guideposts on a changing landscape; agricultural economic report No794.
Chicago-referens (17:e uppl.)USDA och Economic research service. Agri-environment Polisy at the Crossroads: Guideposts on a Changing Landscape; Agricultural Economic Report No794. 2001.
MLA-referens (9:e uppl.)USDA och Economic research service. Agri-environment Polisy at the Crossroads: Guideposts on a Changing Landscape; Agricultural Economic Report No794. 2001.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.