Columbia subject headings:
Catholic Church--History--1965---Congresses.
Christianity--20th century--Congresses.
Secularism--Congresses.
Secularization (Theology)--Congresses.
Harvard subject headings:
Catholic Church--History--20th century.
Catholics.
Princeton subject headings:
Catholic Church--History--1965---Congresses.
Christianity--20th century--Congresses.
Secularism--Congresses.
Secularization (Theology)--Congresses.