Columbia subject headings:
Admission of nonimmigrants--United States.
Tourism--Law and legislation--United States.
United States. Immigration and Naturalization Service.
Visas--United States.
Harvard subject headings:
Admission of nonimmigrants--United States.
Tourism--Law and legislation--United States
United States. Immigration and Naturalization Service.
Visas--United States.
Princeton subject headings:
Admission of nonimmigrants--United States.
Tourism--Law and legislation--United States.
United States. Immigration and Naturalization Service
Visas--United States.