Listen to Viola Sonata in D Minor (Unfinished): I. Allegro moderato online. Viola Sonata in D Minor (Unfinished): I. Allegro moderato is an Instrumental language song and is sung by Michael Kugel and Boris Berezovsky. Viola Sonata in D Minor (Unfinished): I. Allegro moderato, from the album Michael Kugel & Boris Berezovsky: Glinka, Rubinstein, Glazunov, was released in the year 2014. The duration of the song is 9:18. Download Instrumental songs online from JioSaavn.