Question: The pieces Pictures at an Exhibition are composed by a Russian composer who belonged to this group known as what?
Sentence (from "Dmitri Capyrin"): Among the performers of his music there are Yvar Mikhashoff, Claude Delangle, Marc Sieffert, Valery Popov, Moscow Contemporary Music Ensemble, Russian National Orchestra, National Academic Symphonic Band of Ukraine, Kyiv Sinfonietta, Da Capo Chamber Players.
Relevant evidence: No