Columbia subject headings:
Germany--Foreign relations--1933-1945.
Germany--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Germany.
Soviet Union--History--German occupation, 1941-1944.
World War, 1939-1945--Causes.
World War, 1939-1945--Soviet Union.
Harvard subject headings:
Germany--Foreign relations--1933-1945.
Germany--Foreign relations--Soviet Union.
Soviet Union--Foreign relations--Germany.
Soviet Union--History--1939-1945.
Soviet Union--History--German occupation, 1941-1944.
World War, 1939-1945--Causes.
World War, 1939-1945--Soviet Union.
Princeton subject headings:
Soviet Union--History--1925-1953.
World War, 1939-1945--Soviet Union.