Columbia subject headings:
Catholic Church--Manuscripts--Handbooks, manuals, etc.
Catholic Church. Antiphonary--Manuscripts--Handbooks, manuals, etc.
Catholic Church. Breviary--Manuscripts--Handbooks, manuals, etc.
Catholic Church. Gradual (Pre-Vatican II)--Manuscripts--Handbooks, manuals, etc.
Catholic Church. Missal--Manuscripts--Handbooks, manuals, etc.
Gregorian chants--History and criticism.
Liturgics--History--Sources.
Liturgies, Early Christian--History--Sources.
Liturgies--Manuscripts--Handbooks, manuals, etc.
Liturgies--Manuscripts--History.
Liturgies--Manuscripts--Terminology.
Manuscripts, Latin (Medieval and modern)
Manuscripts, Latin (Medieval and modern)--Handbooks, manuals, etc.
Harvard subject headings:
Catholic Church--Liturgy--Manuscripts.
Catholic Church--Liturgy--Sources.
Manuscripts, Latin (Medieval and modern)
Princeton subject headings:
Catholic Church--Liturgy--Manuscripts.
Divine office--Manuscripts.
Manuscripts, Latin (Medieval and modern)
Mass--Prayers and devotions--Manuscripts.