Columbia subject headings:
Harvard subject headings:
Emigration and immigration--Congresses
Emigration and immigration--Government policy--Congresses
Migration, Internal--Europe--Congresses.
Refugees--Congresses
Princeton subject headings:
Emigration and immigration--Congresses.
Emigration and immigration--Government policy--Congresses.
Migration, Internal--Europe--Congresses.
Refugees--Congresses.