Columbia subject headings:
Barth, Karl, 1886-1968.
Bonhoeffer, Dietrich, 1906-1945.
Bultmann, Rudolf, 1884-1976.
Niebuhr, Reinhold, 1892-1971.
Theology, Doctrinal--History--20th century.
Tillich, Paul, 1886-1965.
Harvard subject headings:
Theology, Doctrinal--History--20th century.
Princeton subject headings: