Columbia subject headings:
Catholic Church--Relations--Orthodox Eastern Church.
Orthodox Eastern Church--Relations--Catholic Church.
Orthodox Eastern Church.
Harvard subject headings:
Catholic Church--Relations--Orthodox Eastern Church.
Orthodox Eastern Church--Doctrines.
Orthodox Eastern Church--Relations--Catholic Church.
Princeton subject headings:
Catholic Church--Relations--Orthodox Eastern Church.
Orthodox Eastern Church--Doctrinal and controversial works.
Orthodox Eastern Church--Relations--Catholic Church.