Columbia subject headings:
Communism--Europe--Congresses.
Communist parties--Europe--Congresses.
Nationalism and socialism--Europe--Congresses.
Harvard subject headings:
Communism--Europe--Congresses
Communist parties--Europe--Congresses.
Nationalism and communism--Europe--Congresses.
Nationalism and socialism--Europe--Congresses.
Princeton subject headings:
Communism--Europe--Congresses.
Communist parties--Europe--Congresses.
Nationalism and socialism--Europe--Congresses.