Columbia subject headings:
Germany--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Germany.
World War, 1939-1945--Causes.
Harvard subject headings:
Germany--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Germany.
World War, 1939-1945--Causes.
Princeton subject headings:
Germany--Foreign relations--1933-1945.
Germany--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--1917-1945.
Soviet Union--Foreign relations--Germany.