Columbia subject headings:
Catholic Church--Foreign relations--Soviet Union--Sources.
Soviet Union--Church history--Sources.
Soviet Union--Foreign relations--Catholic Church--Sources.
Harvard subject headings:
Catholic Church--Foreign relations--Russia--Sources.
Catholic Church--Foreign relations--Soviet Union--Sources.
Russia--Church history--1801-1917--Sources.
Russia--Foreign relations--Catholic Church--Sources.
Soviet Union--Church history--Sources.
Soviet Union--Foreign relations--Catholic Church--Sources.
Princeton subject headings:
Catholic Church--Foreign relations--Russia--Sources.
Russia--Church history--Sources.
Russia--Foreign relations--Catholic Church--Sources.