Columbia subject headings:
Castles--Germany--Baden-Württemberg.
Castles--Switzerland.
Fortification--Germany--Baden-Württemberg.
Fortification--Switzerland.
Harvard subject headings:
Castles--Germany--Baden-Württemberg.
Castles--Switzerland
Fortification--Germany--Baden-Württemberg.
Fortification--Switzerland
Princeton subject headings:
Castles--Germany (West)--Baden-Württemberg.
Castles--Switzerland.
Fortification--Germany (West)--Baden-Württemberg.
Fortification--Switzerland.