Columbia subject headings:
Harvard subject headings:
Catholic Church--History--1965---Congresses.
Paul VI, Pope, 1897-1978--Congresses.
Vatican Council (2nd : 1962-1965 : Basilica di San Pietro in Vaticano)--Congresses.
Princeton subject headings:
Catholic Church--History--1965---Congresses.
Paul VI, Pope, 1897-1978--Congresses.