Columbia subject headings:
Harvard subject headings:
Europe, Central--History--20th century--Congresses.
Europe, Central--Politics and government--20th century--Congresses.
Humanities--History--20th century--Congresses.
Literature, Modern--20th century--History and criticism--Congresses
Philosophy--History--20th century--Congresses.
Princeton subject headings:
Europe, Central--History--20th century--Congresses.
Europe, Central--Politics and government--20th century--Congresses.