Columbia subject headings:
Poland--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Poland.
World War, 1939-1945--Causes.
World politics--1933-1945.
Harvard subject headings:
Europe--Politics and government--1918-1945.
Poland--Foreign relations--1918-1945
Poland--Foreign relations--Soviet Union
Soviet Union--Foreign relations--Poland.
Princeton subject headings:
Europe--Politics and government--1918-1945.
Poland--Foreign relations--1918-1945.
Poland--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Poland.