Columbia subject headings:
Strategy--Political aspects--Soviet Union--History--20th century.
World War, 1939-1945--Soviet Union.
Harvard subject headings:
Soviet Union--Foreign relations--1917-1945.
Soviet Union--Politics and government--1936-1953.
World War, 1939-1945--Soviet Union.
Princeton subject headings:
World War, 1939-1945--Causes.
World War, 1939-1945--Soviet Union.