Columbia subject headings:
Emigration and immigration--Congresses.
Ethnology--Europe--Congresses.
Migration, Internal--Europe--Congresses.
Social change--Europe--Congresses.
Social mobility--Europe--Congresses.
Harvard subject headings:
Ethnology--Europe--Congresses
Migration, Internal--Europe--Congresses.
Social change--Europe--Congresses.
Social mobility--Europe--Congresses.
Princeton subject headings: