Columbia subject headings:
Cattedrale di Piacenza--Congresses.
Christian art and symbolism--Italy--Piacenza--Medieval, 500-1500--Congresses.
Church architecture--Italy--Piacenza--Congresses.
Piacenza (Italy)--Buildings, structures, etc.
Harvard subject headings:
Cattedrale di Piacenza--Congresses.
Church architecture--Italy--Congresses.
Piacenza (Italy)--Church history--Congresses.
Princeton subject headings:
Cattedrale di Piacenza--Congresses.
Christian art and symbolism--Italy--Piacenza--Medieval, 500-1500--Congresses.
Church architecture--Italy--Piacenza--Congresses.
Piacenza (Italy)--Buildings, structures, etc.