Columbia subject headings:
Borderlands--Congresses.
Boundaries--Congresses.
Ethnology--Europe--Congresses.
Europe--Boundaries--Congresses.
Europe--Social conditions--Congresses.
Harvard subject headings:
Borderlands--Congresses.
Boundaries--Congresses.
Ethnology--Europe--Congresses
Europe--Boundaries--Congresses.
Europe--Social conditions--Congresses.
Princeton subject headings:
Borderlands--Congresses.
Boundaries--Congresses.
Ethnology--Europe--Congresses.
Europe--Boundaries--Congresses.
Europe--Social conditions--Congresses.