Columbia subject headings:
Admission of nonimmigrants--Government policy--United States.
European Union countries--Foreign relations--United States.
United States--Foreign relations--European Union countries.
Visas--United States.
Harvard subject headings:
Admission of nonimmigrants--Government policy--United States.
European Union countries--Foreign relations--United States.
United States--Foreign relations--European Union countries.
Visas--United States.
Princeton subject headings:
Admission of nonimmigrants--Government policy--United States.
European Union countries--Foreign relations--United States.
United States--Foreign relations--European Union countries.
Visas--United States.