Columbia subject headings:
Catholic Church--Liturgy--Congresses.
Church music--Catholic Church--Congresses.
Music theory--History--500-1400--Congresses.
Tropes (Music)--Congresses.
Harvard subject headings:
Berno, Abbot of Reichenau, -1048
Catholic Church--Liturgy--Congresses.
Church music--Catholic Church--500-1400--Congresses.
Frutolf, -1103.
Hermannus, Contractus, 1013-1054.
Music theory--History--500-1400--Congresses.
Tropes (Music)--Congresses.
Princeton subject headings:
Catholic Church--Liturgy--Congresses.
Church music--Catholic Church--500-1400--Congresses.
Music theory--History--500-1400--Congresses.
Tropes (Music)--Congresses.