Columbia subject headings:
Harvard subject headings:
Archaeology, Medieval--Germany--Ruhr (Region)--Exhibitions.
Art, Medieval--Germany--Ruhr (Region)--Exhibitions.
Ruhr (Germany : Region)--Civilization, Medieval--Exhibitions.
Ruhr (Germany : Region)--Civilization--Exhibitions.
Ruhr (Germany : Region)--History--Exhibitions.
Princeton subject headings:
Archaeology, Medieval--Germany--Ruhr (Region)--Exhibitions.
Art, Medieval--Germany--Ruhr (Region)--Exhibitions.
Civilization, Medieval--Exhibitions.
Ruhr (Germany : Region)--Civilization--Exhibitions.
Ruhr (Germany : Region)--History--Exhibitions.