Columbia subject headings:
Castles--Germany--Rhineland-Palatinate--Guidebooks.
Castles--Germany--Saarland--Guidebooks.
Fortification--Germany--Rhineland-Palatinate--Guidebooks.
Fortification--Germany--Saarland--Guidebooks.
Rhineland-Palatinate (Germany)--Guidebooks.
Saarland (Germany)--Guidebooks.
Harvard subject headings:
Castles--Germany--Rhineland-Palatinate--Guidebooks.
Castles--Germany--Saarland--Guidebooks.
Fortification--Germany--Rhineland-Palatinate--Guidebooks.
Fortification--Germany--Saarland--Guidebooks.
Rhineland-Palatinate (Germany)--Guidebooks.
Saarland (Germany)--Guidebooks.
Princeton subject headings:
Castles--Germany--Rhineland-Palatinate--Guidebooks.
Castles--Germany--Saarland--Guidebooks.
Fortification--Germany--Rhineland-Palatinate--Guidebooks.
Fortification--Germany--Saarland--Guidebooks.
Guidebooks.
Rhineland-Palatinate (Germany)--Guidebooks.
Saarland (Germany)--Guidebooks.