Columbia subject headings:
Germany--History--1945-1955.
Industries--Germany--Ruhr (Region)--History--20th century.
Reconstruction (1939-1951)--Germany--Ruhr (Region)
Ruhr (Germany : Region)--History.
Harvard subject headings:
Germany--History--1945-1955.
Industries--Germany--Ruhr (Region)
Reconstruction (1939-1951)--Germany--Ruhr (Region)
Ruhr (Germany : Region)--History
Princeton subject headings:
Ruhr (Germany : Region)--History.