Columbia subject headings:
Catholic Church--Liturgy--History--Middle Ages, 600-1500--Congresses.
Catholic Church--Liturgy--Theology--Congresses.
Liturgics--History--Congresses.
Theology--History--Middle Ages, 600-1500--Congresses.
Harvard subject headings:
Catholic Church--Liturgy--History--Congresses.
Catholic Church--Liturgy--Theology--Congresses.
Church history--Middle Ages, 600-1500--Congresses.
Liturgics--History--Congresses.
Theology--History--Middle Ages, 600-1500--Congresses
Princeton subject headings: