Columbia subject headings:
Catholic Church. Gradual (Pre-Vatican II)
Gregorian chants--History and criticism.
Music--Manuscripts.
Harvard subject headings:
Catholic Church--Liturgy.
Graduals (Chants)
Gregorian chants--History and criticism.
Music--Manuscripts
Princeton subject headings:
Catholic Church--Liturgy.
Graduals (Chants)
Gregorian chants--History and criticism.
Music--Manuscripts.