Columbia subject headings:
Fortification--Italy--Naples (Kingdom)
Naples (Kingdom)--Defenses.
Naples (Kingdom)--Strategic aspects.
Harvard subject headings:
Fortification--Italy--Naples (Kingdom)
Military architecture--Italy--Naples (Kingdom)--History.
Naples (Kingdom)--Buildings, structures, etc.
Naples (Kingdom)--History, Military.
Princeton subject headings:
Fortification--Italy--Naples (Kingdom).
Naples (Kingdom)--Defenses.
Naples (Kingdom)--History.
Naples (Kingdom)--Strategic aspects.