Columbia subject headings:
Costa, Andrea, 1851-1910--Congresses.
Italy--Politics and government--1870-1914--Congresses.
Socialism--Italy--History--19th century--Congresses.
Harvard subject headings:
Costa, Andrea, 1851-1910--Congresses.
Italy--Politics and government--1870-1914--Congresses.
Socialism--Italy--History--19th century--Congresses.
Princeton subject headings: