Columbia subject headings:
Architecture, Domestic--Germany--Ruhr (Region)
Housing--Germany--Ruhr (Region)
Working class--Dwellings--Germany--Ruhr (Region)
Harvard subject headings:
Architecture, Domestic--Germany--Ruhr (Region)
City planning--Germany--Ruhr (Region)
Housing--Germany--Ruhr (Region)
Ruhr (Germany : Region)--Social conditions
Working class--Dwellings--Germany--Ruhr (Region)
Princeton subject headings:
Architecture, Domestic--Germany (West)--Ruhr River Region.
City planning--Germany (West)--Ruhr River Region.
Working class--Dwellings--Germany (West)--Ruhr River Region.