Columbia subject headings:
Harvard subject headings:
Byzantine chants--History and criticism.
Composers--Bulgaria--Biography
Koukouzelēs, Iōannēs
Music--Bulgaria--500-1400--History and criticism.
Princeton subject headings:
Byzantine chants--History and criticism.
Koukouzelēs, Iōannēs.
Music--Bulgaria--500-1400--History and criticism.