Columbia subject headings:
Harvard subject headings:
Metallurgy--Germany--Westphalia--History.
Mineral industries--Germany--Westphalia--History.
Mines and mineral resources--Germany--Westphalia--History.
Westphalia (Germany)--History.
Princeton subject headings:
Mineral industries--Germany--Westphalia--History.
Mines and mineral resources--Germany--Westphalia--History.
Westphalia (Germany)--History.