Columbia subject headings:
Europe--Foreign relations--United States.
European Union countries--Foreign relations--United States.
North Atlantic Treaty Organization.
United States--Foreign relations--Europe.
United States--Foreign relations--European Union countries.
Harvard subject headings:
Europe--Foreign relations--United States.
European Union countries--Foreign relations--United States.
North Atlantic Treaty Organization
United States--Foreign relations--Europe.
United States--Foreign relations--European Union countries.
Princeton subject headings:
Europe--Foreign relations--United States.
European Union countries--Foreign relations--United States.
North Atlantic Treaty Organization.
United States--Foreign relations--Europe.
United States--Foreign relations--European Union countries.