Columbia subject headings:
Catholic Church--Congresses.
Indulgences--History--Congresses.
Salvation--Christianity--History of doctrines--Middle Ages, 600-1500--Congresses.
Harvard subject headings:
Indulgences--History--To 1500--Congresses.
Salvation--Christianity--History of doctrines--Middle Ages, 600-1500--Congresses.
Princeton subject headings: