Columbia subject headings:
Ferrara (Italy)--History, Military--Sources.
Ferrara (Italy)--History, Military.
Fortification--Italy--Ferrara--History--17th century--Sources.
Fortification--Italy--Ferrara--History--17th century.
Harvard subject headings:
Ferrara (Italy)--History, Military--Sources.
Ferrara (Italy)--History, Military.
Fortification--Italy--Ferrara--History--17th century--Sources.
Fortification--Italy--Ferrara--History--17th century.
Princeton subject headings:
Ferrara (Italy)--History, Military--Sources.
Ferrara (Italy)--History, Military.
Fortification--Italy--Ferrara--History--17th century--Sources.
Fortification--Italy--Ferrara--History--17th century.