an Entity references as follows:
Anna Tomowa-Sintow (Bulgarian: Анна Томова-Синтова, by official transliteration Anna Tomova-Sintova, born September 22, 1941, in Stara Zagora, Bulgaria) is a Bulgarian soprano who has sung to great acclaim in all the major opera houses around the world in a repertoire that includes Mozart, Rossini, Verdi, Puccini, Wagner, and Strauss. She enjoyed a particularly close professional relationship with conductor Herbert von Karajan from 1973 until the conductor's death in 1989. She is also a Kammersängerin of the Vienna Staatsoper.