Columbia subject headings:
Architects--Germany.
City planners--Germany.
City planning--Germany--Ruhr (Region)
Polónyi, Stefan.
Harvard subject headings:
Architects--Germany
City planners--Germany.
City planning--Germany
Polónyi, Stefan.
Princeton subject headings:
Architects--Germany.
City planners--Germany.
City planning--Germany--Ruhr (Region).
Polónyi, Stefan.