Il Trovatore The Troubadour - Fisher, Burton D. (Opera Journeys, 2000)
"Italian opera in four acts, music by Giuseppe Verdi ; libretto by Salvatore Cammarano, after El Trovador (1836), a tragedy by the Spanish playwright, Antonio García Gutiérrez (The final libretto was completed by Emmanuele Bardareafter Cammarano's premature death)."