Columbia subject headings:
Christian socialism--Germany.
Church and state--Germany--History--20th century.
Germany--Church history--20th century.
Socialism and Christianity--Catholic Church--Germany.
Harvard subject headings:
Catholic Church--Germany--History--20th century.
Catholic labor unions--Germany--History.
Church and social problems--Germany--Catholic Church--History.
Deutsche Zentrumspartei--History.
Germany--Politics and government--1918-1933
Princeton subject headings: