Columbia subject headings:
Harvard subject headings:
Bergwerk Minister Stein--History--Catalogs.
Coal mines and mining--Germany--Dortmund--History--Catalogs.
Coal trade--Germany--Dortmund--History--Catalogs.
Princeton subject headings:
Coal mines and mining--Germany--Dortmund--Exhibitions.
Mines and mineral resources--Germany--Dortmund--Exhibitions.
Minister Stein--Exhibitions.