Columbia subject headings:
Graduals (Liturgical books)--Manuscripts.
Harvard subject headings:
Catholic Church--Liturgy.
Manuscripts, Medieval--Italy--Acqui Terme.
Sacred vocal music--Italy--Acqui Terme--Manuscripts.
Princeton subject headings:
Catholic Church--Liturgy.
Manuscripts, Medieval--Italy--Acqui Terme.
Sacred vocal music--Italy--Acqui Terme--Manuscripts.