Columbia subject headings:
Poland--Relations--Soviet Union--Sources.
Soviet Union--Foreign relations--1917-1945--Sources.
Soviet Union--Relations--Poland--Sources.
Harvard subject headings:
Poland--Foreign relations--1918-1945--Sources.
Poland--Foreign relations--Soviet Union--Sources.
Soviet Union--Foreign relations--1917-1945--Sources.
Soviet Union--Foreign relations--Poland--Sources.
Princeton subject headings:
Poland--Relations--Soviet Union--Sources.
Soviet Union--Foreign relations--1917-1945--Sources.
Soviet Union--Relations--Poland--Sources.