| 1. | Berlin: Verlag Ernst Kuhn, 2002, pp. 207–266 ISBN 3-928864-84-X Firsova, Yelena Olegovna by Stephen Johnson, in the New Grove Dictionary of Opera, ed. Berlin: Verlag Ernst Kuhn, 2002, pp. 207-266 (ISBN 3-928864-84-X) (en) Firsova, Yelena Olegovna par Stephen Johnson, dans le New Grove Dictionary of Opera, ed. |