Columbia subject headings:
Catholic Church--Germany--Cologne--Liturgy--History and criticism.
Ordinals (Liturgical books)
Ordinals (Liturgical books)--Texts.
St. Aposteln (Church : Cologne, Germany)--History.
Harvard subject headings:
Catholic Church--Germany--Cologne--Liturgy--History and criticism.
Ordinals (Liturgical books)
Ordinals (Liturgical books)--Texts
St. Aposteln (Church : Cologne, Germany)--History.
Princeton subject headings: