Columbia subject headings:
Industrial archaeology--Germany--Congresses.
Mineral industries--Germany--History--Congresses.
Mines and mineral resources--Germany--History--Congresses.
Harvard subject headings:
Industrial archaeology--Germany--Congresses.
Mineral industries--Germany--History--Congresses.
Mines and mineral resources--Germany--History--Congresses.
Princeton subject headings:
Industrial archaeology--Germany--Congresses.
Mineral industries--Germany--History--Congresses.
Mines and mineral resources--Germany--History--Congresses.