Columbia subject headings:
Harvard subject headings:
Europe--Civilization--20th century--Congresses.
Europe--History--20th century--Congresses.
National characteristics, European--Congresses.
Regionalism--Europe--Congresses
Princeton subject headings:
Europe--Civilization--20th century--Congresses.
Europe--History--20th century--Congresses.
National characteristics, European--Congresses.
Regionalism--Europe--Congresses.