Columbia subject headings:
Communism and Christianity--Soviet Union--Congresses.
Gnosticism--Congresses.
Philosophy, Russian--20th century--Congresses.
Religion--Philosophy--History--Congresses.
Harvard subject headings:
Christianity--Philosophy--History--20th century.
Communism and Christianity--Soviet Union--Congresses.
Gnosticism--Congresses
Orthodox Eastern Church--Russia (Federation)--History--20th century--Congresses.
Philosophy and religion--Congresses.
Philosophy, Russian--20th century--Congresses.
Philosophy, Russian--20th century.
Religion--Philosophy--Congresses
Religion--Philosophy--History--Congresses.
Russkai︠a︡ pravoslavnai︠a︡ t︠s︡erkovʹ--Doctrines--History--20th century--Congresses.
Princeton subject headings:
Communism and Christianity--Soviet Union--Congresses.
Gnosticism--Congresses.
Philosophy, Russian--20th century--Congresses.
Religion--Philosophy--History--Congresses.