Columbia subject headings:
Piazza maggiore (Bologna, Italy)
Plazas--Italy--Bologna.
Harvard subject headings:
Architecture--Italy--Bologna.
Art, Italian--Italy--Bologna.
Piazza maggiore (Bologna, Italy)
Plazas--Italy--Bologna.
Princeton subject headings:
Architecture--Italy--Bologna.
Art, Italian--Italy--Bologna.
Piazza maggiore (Bologna, Italy)
Plazas--Italy--Bologna.