Columbia subject headings:
Authors--20th century--Political and social views--Congresses.
Literature, Modern--20th century--Political aspects--Congresses.
Literature, Modern--20th century--Social aspects--Congresses.
Harvard subject headings:
Authors--20th century--Political and social views--Congresses.
Literature, Modern--20th century--Political aspects--Congresses.
Literature, Modern--20th century--Social aspects--Congresses.
Princeton subject headings:
Authors--Congresses.
Berlin (Germany)--Anniversaries, etc.--Congresses.