Question: Mstislav Rostropovich, Daniil Shafran and Sviatoslav Knushevitsky were leading examples of what kind of musician among 20th century Russians?
Sentence (from "Daniil Shafran"): Daniil Borisovich Shafran (Russian: Даниил Борисович Шафран , January 13, 1923February 7, 1997) was a Soviet Russian cellist.
Relevant evidence: Yes