Columbia subject headings:
Ballet--Dictionaries.
Musicals--History and criticism--Dictionaries.
Opera--Dictionaries.
Operas--Stories, plots, etc.
Harvard subject headings:
Ballet--Dictionaries--German.
Ballet--Dictionaries.
Ballets--Stories, plots, etc.
Musicals--Dictionaries--German.
Musicals--Dictionaries.
Musicals--Stories, plots, etc.
Opera--Dictionaries
Opera--Dictionaries--German
Operas--Stories, plots, etc.
Princeton subject headings:
Ballet--Dictionaries.
Dictionaries.
Opera--Dictionaries.
Operas--Stories, plots, etc.
Revues--History and criticism--Dictionaries.