Columbia subject headings:
Harvard subject headings:
Papal visits--Congresses.
Paul VI, Pope, 1897-1978--Congresses.
Princeton subject headings:
Catholic Church--Foreign relations--Congresses.
Catholic Church--Political activity--History--20th century--Congresses.
Catholic Church. Pope (1963-1978 : Paul VI)--Congresses.
Paul VI, Pope, 1897-1978--Congresses.