Columbia subject headings:
Music--History and criticism.
Musical theater--History.
Musical theater--Italy--History.
Opera--Italy--18th century--History and criticism.
Opera--Italy--19th century--History and criticism.
Harvard subject headings:
Music--History and criticism
Musical theater--History.
Musical theater--Italy--History.
Opera--Italy--18th century
Opera--Italy--19th century
Princeton subject headings:
Musical theater--Italy--18th century.
Musical theater--Italy--19th century.
Musical theater--Italy--20th century.