Columbia subject headings:
Church and state--Communist countries--Congresses.
Church and state--Europe, Eastern--Congresses.
Communism and Christianity--Congresses.
Communism and Christianity--Europe, Eastern--Congresses.
Communist countries--Church history--Congresses.
Europe, Eastern--Church history--Congresses.
Socialism and Christianity--Congresses.
Harvard subject headings:
Church and state--Communist countries--Congresses.
Church and state--Europe, Eastern--Congresses.
Communism and Christianity--Congresses.
Communism and Christianity--Europe, Eastern--Congresses.
Communist countries--Church history--Congresses.
Europe, Eastern--Church history--Congresses.
Socialism and Christianity--Congresses.
Princeton subject headings:
Church and state--Communist countries--Congresses.
Church and state--Europe, Eastern--Congresses.
Communism and Christianity--Congresses.
Communism and Christianity--Europe, Eastern--Congresses.
Communist countries--Church history--Congresses.
Europe, Eastern--Church history--Congresses.
Socialism and Christianity--Congresses.