Columbia subject headings:
Beauduin, Lambert, 1873-1960.
Catholic Church--Relations--Orthodox Eastern Church.
Orthodox Eastern Church--Relations--Catholic Church.
Schism--Eastern and Western Church.
Harvard subject headings:
Beauduin, Lambert, 1873-1960--1873-
Catholic Church--Relations--Orthodox Eastern Church.
Orthodox Eastern Church--Relations--Catholic Church.
Schism--Eastern and Western Church.
Princeton subject headings:
Beauduin, Lambert, 1873-1960--1873-.
Catholic Church--Relations--Orthodox Eastern Church.
Orthodox Eastern Church--Relations--Catholic Church.
Schism--Eastern and Western Church.