Columbia subject headings:
Harvard subject headings:
Catholic Church--Germany--Ruhr (Region)--History--20th century.
Christianity and politics--Germany--Ruhr (Region)--History--20th century.
National socialism and religion--Germany--Ruhr (Region)
National socialism--Religious aspects.
Princeton subject headings:
Catholic Church--Germany--Ruhr (Region)--History--20th century.
Christianity and politics--Germany--Ruhr (Region)--History--20th century.
National socialism and religion--Germany--Ruhr (Region).
National socialism--Religious aspects.