Efrem Flaks was the original performer of songs composed by which other Soviet film composer?
Efrem Flaks:  He was the original performer of numerous songs by composers Vasily Solovyov-Sedoi, Matvey Blanter, Boris Mokrousov, etc. Matvey Blanter: Matvei Isaakovich Blanter (Russian: Матве́й Исаа́кович Бла́нтер ) (10 February [O.S. 28 January] 1903 27 September 1990) was one of the most prominent composers of popular songs and film music in the Soviet Union.
Matvei Isaakovich Blanter