Columbia subject headings:
Harvard subject headings:
Hagia Sophia (Church : İznik, Turkey)--History.
Orthodoxos Ekklēsia tēs Hellados--Hymns--History and criticism.
Orthodoxos Ekklēsia tēs Hellados--Liturgy.
Orthros (Music)--History and criticism.
Vespers (Music)--History and criticism.
Princeton subject headings:
Hagia Sophia (Church : İznik, Turkey)--History.
Orthodoxos Ekklēsia tēs Hellados--Hymns--History and criticism.
Orthodoxos Ekklēsia tēs Hellados--Liturgy.
Orthros (Music)--History and criticism.
Vespers (Music)--History and criticism.