Question: Who is the Estonian composer of classical and religious music that was featured in the recording of twenty one duets for two cellos and piano or harp ranging from the sixteenth to the twenty-first century?
Sentence (from "Arvo Pärt"): His most performed works include "Fratres" (1977), "Spiegel im Spiegel" (1978), and "Für Alina" (1976).
Relevant evidence: No