Columbia subject headings:
Catholic Church--Foreign relations--Europe, Eastern--Congresses.
Catholic Church--Foreign relations--Soviet Union--Congresses.
Catholic Church--Relations--Orthodox Eastern Church--Congresses.
Communism and Christianity--Catholic Church--History--20th century--Congresses.
Europe, Eastern--Foreign relations--1945-1989--Congresses.
Europe, Eastern--Foreign relations--Catholic Church--Congresses.
Orthodox Eastern Church--Relations--Catholic Church--Congresses.
Orthodox Eastern Church--Soviet Union--History--20th century--Congresses.
Soviet Union--Foreign relations--1945-1991--Congresses.
Soviet Union--Foreign relations--Catholic Church--Congresses.
Harvard subject headings:
Princeton subject headings:
Catholic Church--Foreign relations--Europe, Eastern--Congresses.
Catholic Church--Foreign relations--Soviet Union--Congresses.
Catholic Church--Relations--Orthodox Eastern Church--Congresses.
Communism and Christianity--Catholic Church--History--20th century--Congresses.
Europe, Eastern--Foreign relations--1945-1989--Congresses.
Europe, Eastern--Foreign relations--Catholic Church--Congresses.
Orthodox Eastern Church--Relations--Catholic Church--Congresses.
Orthodox Eastern Church--Soviet Union--History--20th century--Congresses.
Soviet Union--Foreign relations--1945-1991--Congresses.
Soviet Union--Foreign relations--Catholic Church--Congresses.