*Scott, Michael (1977), "The Record of Singing", volume one, 243 pages, ISBN 0-7156-1030-9*Warrack, John and West, Ewan (1992), "The Oxford Dictionary of Opera", 782 pages, ISBN 0-19-869164-5
* Warrack, John and West, Ewan (1992), "The Oxford Dictionary of Opera", 782 pages, ISBN 0-19-869164-5* Obituary article in "il Mattino" (Naples), April 24, 1950.