Columbia subject headings:
Biblioteca Nacional (Spain)
Cities and towns--Italy--Sicily--History--17th century.
Fortification--Italy--Sicily--Early works to 1800.
Fortification--Italy--Sicily--History--17th century.
Harvard subject headings:
Cities and towns--Italy--Sicily--History--17th century.
Fortification--Italy--Sicily--History--17th century.
Princeton subject headings:
Cities and towns--Italy--Sicily--History--17th century.
Fortification--Italy--Sicily--History--17th century.