Columbia subject headings:
Harvard subject headings:
City planning--Germany--Ruhr (Region)
Ruhr (Germany : Region)--History
Ruhr (Germany : Region)--Pictorial works.
Social change--Germany--Ruhr (Region)
Sociology, Urban--Germany--Ruhr (Region)
Princeton subject headings:
City planning--Germany--Ruhr (Region).
Ruhr (Germany : Region)--History.
Ruhr (Germany : Region)--Pictorial works.
Social change--Germany--Ruhr (Region).
Sociology, Urban--Germany--Ruhr (Region).