Columbia subject headings:
Anarchism--Italy--History--Congresses.
Socialism--Italy--History--Congresses.
Syndicalism--Italy--History--Congresses.
Harvard subject headings:
Anarchism--Italy--History--Congresses.
Anarchism--Italy--Veneto--History--Congresses.
Labor unions--Italy--Veneto--Political activity--History--Congresses.
Socialism--Italy--Congresses
Socialism--Italy--History--Congresses.
Socialism--Italy--Veneto--History--Congresses.
Syndicalism--Italy--History--Congresses.
Princeton subject headings:
Anarchism--Italy--Veneto--History--Congresses.
Labor unions--Italy--Veneto--Political activity--History--Congresses.
Socialism--Italy--Veneto--History--Congresses.