Columbia subject headings:
Emigration and immigration--Congresses.
Foreign workers--Congresses.
Refugees--Congresses.
Refugees--Legal status, laws, etc.--Congresses.
Harvard subject headings:
Emigration and immigration--Congresses
Foreign workers--Congresses.
Refugees--Congresses
Refugees--Legal status, laws, etc.--Congresses.
Princeton subject headings:
Political refugees--Legal status, laws, etc.