Columbia subject headings:
Iron industry and trade--Germany--Harz Mountains--History.
Metal trade--Germany--Harz Mountains--History.
Mineral industries--Germany--Harz Mountains--History.
Harvard subject headings:
Iron industry and trade--Germany--Harz Mountains--History.
Metal trade--Germany--Harz Mountains--History.
Mineral industries--Germany--Harz Mountains--History.
Princeton subject headings:
Iron industry and trade--Germany--Harz Mountains--History.
Metal trade--Germany--Harz Mountains--History.
Mineral industries--Germany--Harz Mountains--History.