Columbia subject headings:
Castles--France--Guidebooks.
Fortification--France--Guidebooks.
Military architecture--France--Guidebooks.
Harvard subject headings:
Castles--France--Guidebooks.
Fortification--France--Guidebooks.
Military architecture--France--Guidebooks.
Princeton subject headings:
Castles--France--Guidebooks.
Fortification--France--Guidebooks.