Columbia subject headings:
Anarchism--History--20th century--Congresses.
World War, 1914-1918--Congresses.
Harvard subject headings:
Anarchism--History--20th century--Congresses.
World War, 1914-1918--Congresses
Princeton subject headings:
Anarchism--History--20th century--Congresses.
World War, 1914-1918--Congresses.