Columbia subject headings:
Emigration and immigration.
Foreign trade and employment.
Foreign workers.
Labor policy.
Harvard subject headings:
Economic development--Congresses
Emigration and immigration
Emigration and immigration--Congresses
Foreign trade and employment--Congresses.
Foreign trade and employment.
Foreign workers
Foreign workers--Congresses.
Labor policy
Labor policy--Congresses
Princeton subject headings:
Economic development--Congresses.
Emigration and immigration--Congresses.
Foreign trade and employment--Congresses.
Foreign workers--Congresses.
Labor policy--Congresses.