Khovanshchina: Act I: Introduction — Sofia National Opera Orchestra, Nicola Ghiuselev, Dimitar Petkov, Bulgarian National Svetoslav Obretenov Choir, Todor Kostov, Alexandrina Milcheva, Maria Dimchevska, Najejda Dobrianova, Ljubomir Bodourov, Dimiter Dimitrov, Stoyan Popov, Verter Vrachovsky, Milen Paounov, Stefan Elenkov, Nedelcho Pavlov & Atanas Margaritov