Columbia subject headings:
Bonhoeffer, Dietrich, 1906-1945.
Luther, Martin, 1483-1546.
Harvard subject headings:
Bonhoeffer, Dietrich, 1906-1945
Luther, Martin, 1483-1546
Princeton subject headings:
Bonhoeffer, Dietrich, 1906-1945.
Luther, Martin, 1483-1546.