Columbia subject headings:
Liber magistri--Congresses.
Music--Italy--500-1400.
Music--Manuscripts--Italy--Piacenza--Congresses.
Harvard subject headings:
Catholic Church. Liber magistri (Ms. Liber magistri)--Congresses.
Gregorian chants--Italy--Piacenza--500-1400--Manuscripts--Congresses.
Princeton subject headings:
Biblioteca capitolare (Piacenza, Italy). Manuscript. 65--Congresses.
Church music--500-1400--Congresses.
Liber magistri.