Columbia subject headings:
Basilica di San Petronio (Bologna, Italy)--History--Congresses.
Harvard subject headings:
Basilica di San Petronio (Bologna, Italy)--History--Congresses.
Bologna (Italy)--Buildings, structures, etc.--Congresses.
Bologna (Italy)--Church history--Congresses.
Princeton subject headings:
Basilica di San Petronio (Bologna, Italy)--Congresses.
Bologna (Italy)--Buildings, structures, etc.--Congresses.