Columbia subject headings:
Christian union--Congresses.
Christian union--Orthodox Eastern Church--Congresses.
Ecumenical movement--Congresses.
Ecumenical movement--Orthodox Eastern Church--Congresses.
Orthodox Eastern Church--Relations--Congresses.
Harvard subject headings:
Christian union--Orthodox Eastern Church--Congresses.
Ecumenical movement--Congresses.
Orthodox Eastern Church--Relations--Congresses.
Princeton subject headings: