Autorités BnF, data.bnf.fr, besøkt 10. oktober 2015[Hentet fra Wikidata]
digitalarchivioricordi.com
Archivio Storico Ricordi, Archivio Storico Ricordi person-ID 216, besøkt 3. desember 2020[Hentet fra Wikidata]
discogs.com
Discogs, Discogs artist-ID 1341436, besøkt 9. oktober 2017[Hentet fra Wikidata]
nytimes.com
query.nytimes.com
«$2,000 Baritone Says the Art of Song Is Declining in Italy – Likes Shakespearean Roles.». The New York Times. 29. oktober 1912. Besøkt 21. desember 2009. «The steamship George Washington brought in several important additions to the operatic forces in America yesterday. Its passenger list included the names of Titta Ruffo, the $2,000 baritone, and Lucrezia Bori, the Spanish soprano. Besides Ruffo there were three other baritones on board – Antonio Scotti, Pasquale Amato, and William Hinshaw.»