Columbia subject headings:
Harvard subject headings:
Bologna (Italy)--Emigration and immigration--Congresses.
Bologna (Italy)--Social conditions--Congresses.
Immigrants--Italy--Bologna--Congresses.
Immigrants--Italy--Bologna--Social conditions--Congresses.
Princeton subject headings:
Bologna (Italy)--Congresses.
Bologna (Italy)--Emigration and immigration--Congresses.
Immigrants--Italy--Bologna--Congresses.