The troubadour :
an opera in four acts /
by Giuseppe Verdi ; English words by Theodore T. Barker.
APA Citation
Verdi, G., García Gutiérrez, A., Cammarano, S., Barker, T. T. (1890). The troubadour: an opera in four acts. New York: C. F. Tretbar.
MLA Citation
Verdi, Giuseppe, 1813-1901, Antonio García Gutiérrez, Salvatore Cammarano, and Theodore T Barker. The Troubadour: an Opera In Four Acts. New York: C. F. Tretbar, 1890.
Warning: These citations may not always be complete (especially for serials).