1. Garibaldi, Luigi Agostino, Giuseppe Verdi nelle lettere di Emanuele Muzio ad Antonio Barezzi, Milano: Treves 1931.
2. Gossett, Philip, The Hot and the Cold: Verdi Writes to Antonio Somma About »Re Lear«, in: Variations on the Canon: Essays on Music from Bach to Boulez in Honor of Charles Rosen on his Eightieth Birthday, hrsg. von Robert Curry, David Gable und Robert L[ewis] Marshall, Rochester, NY: University of Rochester Press 2008, S. 207–244.
3. Marvin, Roberta Montemorra, Verdi’s Unwritten Operas, in: The Maynooth International Musicological Conference 1995: Selected Proceedings, hrsg. von Patrick F. Devine und Harry White, Bd. II (Irish Musical Studies, 5), Dublin: Four Courts 1996, S. 191–204.
4. Mossa, Carlo Matteo, A Monk and At Least Some New Things: Verdi, Cammarano, and » L’assedio di Firenze«, in: Verdi’s Middle Period (1849–1859): Source Studies, Analysis, and Performance Practice, hrsg. von Martin Chusid, Chicago: The University of Chicago Press 1997, S. 99–126.
5. Nardi, Piero, Vita di Arrigo Boito, Verona: Mondadori 1942.