Columbia subject headings:
Music--Manuscripts--Facsimiles.
Operas--Librettos.
Operas--Scores.
Harvard subject headings:
Music--Manuscripts--Facsimiles
Operas--Librettos
Operas--Scores
Princeton subject headings:
Music--Manuscripts--Facsimiles.
Operas--Librettos.
Operas--Scores.
Operas.
Scores.