Columbia subject headings:
Communism--Congresses.
Marx, Karl, 1818-1883--Congresses.
Philosophy, Marxist--Congresses.
Harvard subject headings:
Communism--Congresses
Marx, Karl, 1818-1883--Congresses.
Philosophy, Marxist--Congresses.
Princeton subject headings:
Communism--Congresses.
Marx, Karl, 1818-1883--Congresses.
Philosophy, Marxist--Congresses.