Columbia subject headings:
De Ambris, Alceste, 1874-1934.
Labor leaders--Italy--Biography.
Socialists--Italy--Biography.
Harvard subject headings:
De Ambris, Alceste, 1874-1934.
Labor unions--Political activity--Italy--History--20th century.
Syndicalism--Italy--History--20th century.
Princeton subject headings:
Ambris, Alceste de.
Labor unions--Italy--Political activity--History--20th century.
Syndicalism--Italy--History--20th century.