Columbia subject headings:
Catholic Church--Relations--Orthodox Eastern Church--Periodicals.
Christian union--Catholic Church--Periodicals.
Istituto di teologia ecumenica S. Nicola--Periodicals.
Harvard subject headings:
Catholic Church--Relations--Orthodox Eastern Church--Periodicals.
Christian union--Catholic Church--Periodicals.
Istituto di teologia ecumenica S. Nicola--Periodicals.
Princeton subject headings: