Columbia subject headings:
Harvard subject headings:
Archives--Germany--Ennepe-Ruhr-Kreis.
Castles--Germany--Ennepe-Ruhr-Kreis--History.
Ennepe-Ruhr-Kreis (Germany)--Antiquities.
Excavations (Archaeology)--Germany--Ennepe-Ruhr-Kreis.
Kreisarchiv Ennepe-Ruhr-Kreis--History.
Steel industry and trade--Germany--Ennepe-Ruhr-Kreis--History.
Princeton subject headings:
Archives--Germany--Ennepe-Ruhr-Kreis.
Castles--Germany--Ennepe-Ruhr-Kreis--History.
Ennepe-Ruhr-Kreis (Germany)--Antiquities.
Excavations (Archaeology)--Germany--Ennepe-Ruhr-Kreis.
Kreisarchiv des Ennepe-Ruhr-Kreises--History.
Steel industry and trade--Germany--Ennepe-Ruhr-Kreis--History.