Columbia subject headings:
Harvard subject headings:
Caves--Collectibles--Exhibitions.
Gussmann, Karl, 1853-1928--Exhibitions.
Speleologists--Germany--Swabia--Biography--Exhibitions.
Speleology--Germany--Swabia--History--Exhibitions.
Princeton subject headings:
Caves--Collectibles--Exhibitions.
Gussmann, Karl, 1853-1928--Exhibitions.
Speleologists--Germany--Swabia--Biography--Exhibitions.
Speleology--Germany--Swabia--History--Exhibitions.