Sofia Ecclestiastical Choir

Greek Orthodox Polyphonic Chorus of Anthens

Belgrade Singing Society

St. Cyril & Methodius Ukrainian Church Choir

Russian Choir of the Holy Blood Church

St. Michael's Romanian Church Choir

Armenian Apostolic Chorus of Jerusalem

Greek Orthodox triphonic Chorus of Athens

Georgian Orthodox Choir of Tiflis

Greek Orthodox Tetraphonic Chorus

Greek Orthodox Triphonic Chorus of Anthens