APA (7th ed.) Citation

Verdi, G. (1957). Un ballo in maschera (A masked ball): Opera in three acts. G. Schirmer.

Chicago Style (17th ed.) Citation

Verdi, Giuseppe. Un Ballo in Maschera (A Masked Ball): Opera in Three Acts. New York: G. Schirmer, 1957.

MLA (9th ed.) Citation

Verdi, Giuseppe. Un Ballo in Maschera (A Masked Ball): Opera in Three Acts. G. Schirmer, 1957.