Columbia subject headings:
Harvard subject headings:
European Union countries--Foreign economic relations--United States.
Non-tariff trade barriers--European Union countries.
Non-tariff trade barriers--United States.
United States--Foreign economic relations--European Union countries.
Princeton subject headings:
European Union countries--Foreign economic relations--United States.
Non-tariff trade barriers--European Union countries.
Non-tariff trade barriers--United States.
United States--Foreign economic relations--European Union countries.