Columbia subject headings:
Christian union.
Ecumenical movement.
Theology.
Harvard subject headings:
Catholic Church. Pontificium Consilium ad Christianorum Unitatem Fovendam
Christian union
Ecumenical movement
Jaeger, Lorenz, 1892-1975
Stakemeier, Eduard.
Theology
Vatican Council (2nd : 1962-1965 : Basilica di San Pietro in Vaticano)
Princeton subject headings: