Columbia subject headings:
Dramatic music--History and criticism--Congresses.
Music--Performance--Congresses.
Opera--Congresses.
Harvard subject headings:
Music--Congresses
Music--Performance
Music--Performance--Congresses.
Musicals
Musicals--Congresses.
Opera
Opera--Congresses
Princeton subject headings:
Music--Congresses.
Music--Performance--Congresses.
Music--Performance.
Musicals--Congresses.
Musicals.
Opera--Congresses.
Opera.