Columbia subject headings:
Harvard subject headings:
Christian saints--Cult--Europe.
Christian saints--Songs and music.
Gregorian chants.
Liturgies, Early Christian.
Sacred vocal music--500-1400.
Princeton subject headings:
Alcuin, 735-804--Musical settings.
Gregorian chants.
Rhymed offices.
Willibrord, Saint, 658?-739--Songs and music.