Columbia subject headings:
Foreign worker certification--United States.
Foreign workers certification--United States.
Foreign workers--Government policy--United States.
United States--Emigration and immigration--Government policy.
Visas--United States.
Harvard subject headings:
Foreign worker certification--United States
Foreign workers certification--United States.
Foreign workers--Government policy--United States
United States--Emigration and immigration--Government policy.
Visas--United States.
Princeton subject headings:
Foreign workers certification--United States.
Foreign workers--Government policy--United States.
United States--Emigration and immigration--Government policy.
Visas--United States.