Columbia subject headings:
Operas--17th century--Librettos.
Operas--18th century--Librettos.
Harvard subject headings:
Facsimiles
Librettos
Operas--17th century--Librettos.
Operas--18th century--Librettos.
Princeton subject headings:
Operas--17th century--Librettos.
Operas--18th century--Librettos.