Columbia subject headings:
Harvard subject headings:
Humboldt, Alexander von, 1769-1859--Congresses.
Humboldt-Forum (Berlin, Germany)--History--Congresses.
Mineral industries--Germany--Ansbach (Mittelfranken)--History--Congresses.
Mineral industries--Germany--Bayreuth--History--Congresses.
Mines and mineral resources--Germany--Ansbach (Mittelfranken)--History--Congresses.
Mines and mineral resources--Germany--Bayreuth--History--Congresses.
Naturalists--Germany--Franconia--Biography--Congresses.
Statesmen--Germany--Franconia--Biography--Congresses.
Princeton subject headings:
Humboldt, Alexander von, 1769-1859--Congresses.
Humboldt-Forum (Berlin, Germany)--History--Congresses.
Mineral industries--Germany--Ansbach (Mittelfranken)--History--Congresses.
Mineral industries--Germany--Bayreuth--History--Congresses.
Mines and mineral resources--Germany--Ansbach (Mittelfranken)--History--Congresses.
Mines and mineral resources--Germany--Bayreuth--History--Congresses.
Naturalists--Germany--Franconia--Biography--Congresses.
Statesmen--Germany--Franconia--Biography--Congresses.