Columbia subject headings:
Catholic Church--Doctrines.
Congar, Yves, 1904-1995.
Harvard subject headings:
Catholic Church--Doctrines--History--20th century.
Christian union--History of doctrines.
Church--Unity--History of doctrines.
Congar, Yves, 1904-1995
Ecumenical movement--Catholic Church.
Ecumenical movement.
Princeton subject headings: