Columbia subject headings:
Castles--Italy--Guidebooks.
Fortification--Italy--Guidebooks.
Harvard subject headings:
Castles--Italy--Friuli-Venezia Giulia--Guidebooks.
Fortification--Italy--Friuli-Venezia Giulia--Guidebooks.
Friuli Venezia Giulia (Italy)--Buildings, structures, etc.--Guidebooks.
Friuli Venezia Giulia (Italy)--Guidebooks.
Princeton subject headings:
Castles--Italy--Friuli-Venezia Giulia--Guidebooks.
Fortification--Italy--Friuli-Venezia Giulia--Guidebooks.
Friuli Venezia Giulia (Italy)--Buildings, structures, etc.--Guidebooks.
Friuli Venezia Giulia (Italy)--Description and travel--Guidebooks.
Guidebooks.