Columbia subject headings:
Harvard subject headings:
Castles--Germany--Schleswig-Holstein.
Fortification--Germany--Schleswig-Holstein.
Germany (West)--Antiquities, Slavic.
Schleswig-Holstein (Germany)--Antiquities, Slavic.
Slavs--Germany--Schleswig-Holstein.
Princeton subject headings:
Castles--Germany--Schleswig-Holstein.
Excavations (Archaeology)--Germany--Schleswig-Holstein.
Schleswig-Holstein (Germany)--Antiquities.