Columbia subject headings:
Catholic Church--Foreign relations--Communist countries.
Catholic Church--Foreign relations--Europe, Eastern.
Communist countries--Foreign relations--Catholic Church.
Europe, Eastern--Foreign relations--Catholic Church.
Harvard subject headings:
Catholic Church--Foreign relations--Communist countries.
Catholic Church--Foreign relations--Europe, Eastern.
Communist countries--Relations--Catholic Church.
Europe, Eastern--Relations--Catholic Church.
Princeton subject headings:
Catholic Church--Foreign relations--Europe, Eastern.
Europe, Eastern--Foreign relations--Catholic Church.