Columbia subject headings:
Dueling--Italy--Naples--History--19th century.
Dueling--Italy--Naples--History--20th century.
Harvard subject headings:
Dueling--Italy--Naples--History--19th century.
Dueling--Italy--Naples--History--20th century.
Princeton subject headings:
Dueling--Italy--Naples--History--19th century.
Dueling--Italy--Naples--History--20th century.