http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Libretto by Antonio Somma (Freely adapted after Eugene Scribe's "Gustave ou Le bal masque") English version by Peter Paul Fuchs.
Italian and English on opposite pages, numbered in duplicate.
G. Schirmer's collection of opera librettos