Columbia subject headings:
Harvard subject headings:
Fortification--Italy--Perugia.
Paolina Fort (Perugia, Italy)--Guidebooks.
Perugia (Italy)--Buildings, structures, etc.--Guidebooks.
Princeton subject headings:
Guidebooks.
Paolina Fort (Perugia, Italy)--Guidebooks.
Perugia (Italy)--Buildings, structures, etc.--Guidebooks.