Columbia subject headings:
Anarchism in literature--Congresses.
Anarchism--Spain--History--Congresses.
Press, Anarchist--Spain--Congresses.
Harvard subject headings:
Anarchism in literature--Congresses.
Anarchism--Spain--History--Congresses.
Press, Anarchist--Spain--Congresses.
Princeton subject headings:
Anarchism in literature--Congresses.
Anarchism--Spain--History--Congresses.
Press, Anarchist--Spain--Congresses.