Un ballo in maschera : melodramma in tre atti / musica di G. Verdi.

Libretto by A. Somma, based on Scribe's Gustave III. Cf. Loewenberg, Annals of Opera.
First complete vocal score of the opera published in France; engraved.
Collation: t.p.: p. [1]; "Indice" [sic] and "Personaggi": p. [3]; table of contents: p. [4]; music: p. 1-280.
The "Indice" (= table of contents) does not appear on p. [3], but rather on p. [4].