Columbia subject headings:
Mozart, Wolfgang Amadeus, 1756-1791. Operas.
Operas--Librettos.
Harvard subject headings:
Mozart, Wolfgang Amadeus, 1756-1791. Operas.
Operas--Librettos
Princeton subject headings:
Librettos.
Mozart, Wolfgang Amadeus, 1756-1791. Operas.
Operas--Librettos.