an Entity references as follows:
Bohumil Gregor (14 July 1926 – 4 November 2005) was a Czech conductor. Gregor was born and died in Prague. He studied double bass at the Prague Conservatory. He made his conducting debut on October 26, 1947, at the Divadlo 5. května (Theatre of the Fifth of May, now the Prague State Opera). He conducted at the State Theatre in Brno (1949–1951), the National Theatre in Prague (1955–1958 and 1962–1966), the State Theatre in Ostrava (1958–1962), the Royal Swedish Opera in Stockholm (1966–1969), the State Opera in Hamburg (1969–1972), De Nederlandse Opera in Amsterdam (from 1972), and also in San Francisco, Philadelphia and Washington. In 1999, he returned to the Prague State Opera where he worked as musical director until 2002.