Columbia subject headings:
Castles--Italy--Abruzzo--Pictorial works.
Castles--Italy--Lazio--Pictorial works.
Castles--Pictorial works.
Fortification--Italy--Abruzzo--Pictorial works.
Fortification--Italy--Lazio--Pictorial works.
Harvard subject headings:
Abruzzo (Italy)--Pictorial works.
Castles--Italy--Lazio--Pictorial works.
Fortification--Italy--Lazio--Pictorial works.
Lazio (Italy)--Pictorial works.
Princeton subject headings:
Castles--Italy--Abruzzo--Pictorial works.
Castles--Italy--Lazio--Pictorial works.
Castles--Pictorial works.
Fortificaiton--Italy--Abruzzo--Pictorial works.
Fortification--Italy--Lazio--Pcitorial works.