Columbia subject headings:
Germany--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Germany.
World War, 1939-1945--Diplomatic history.
World War, 1939-1945--Soviet Union.
Harvard subject headings:
Germany--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Germany.
World War, 1939-1945--Diplomatic history.
World War, 1939-1945--Soviet Union.
Princeton subject headings:
World War, 1939-1945--Diplomatic history.
World War, 1939-1945--Secret service.