557 Violetta: differenze tra le versioni

* {{cita libro|Lutz D.|Schmadel|wkautore=Lutz D. Schmadel|Dictionary of Minor Planet Names, 5th ed.: <small>Prepared on Behalf of Commission 20 Under the Auspices of the [[International Astronomical Union]]</small>|url=http://books.google.it/books?id=KWrB1jPCa8AC&printsec=frontcover&dq=editions:ISBN3642019641&client=firefox-a#v=onepage&q=&f=false|2003|Springer|Berlin, New York|idisbn=ISBN 3-540-00238-3}}