USDA & Economic research service. (2001). Agri-environment polisy at the crossroads: Guideposts on a changing landscape; agricultural economic report No794.
Chicago-viite (17. p.)USDA ja Economic research service. Agri-environment Polisy at the Crossroads: Guideposts on a Changing Landscape; Agricultural Economic Report No794. 2001.
MLA-viite (9. p.)USDA ja Economic research service. Agri-environment Polisy at the Crossroads: Guideposts on a Changing Landscape; Agricultural Economic Report No794. 2001.
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