Columbia subject headings:
Church music--Italy--Bologna--History and criticism--Congresses.
Harvard subject headings:
Church music--Catholic Church--Congresses.
Church music--Italy--20th century--Congresses.
Church music--Italy--Bologna--Congresses.
Princeton subject headings:
Church music--Catholic Church--Congresses.
Church music--Italy--20th century--Congresses.
Church music--Italy--Bologna--Congresses.