ISBN 9781445604459 ISBN 1-4456-0445-0* Keolker, James, "Last Acts, The Operas of Puccini and His Italian Contemporaries", 2001.
ISBN 9781445604459 ISBN 1-4456-0445-0* Keolker, James, «Last Acts, The Operas of Puccini and His Italian Contemporaries», 2001.