Columbia subject headings:
Harvard subject headings:
Germany--History, Military--20th century.
World War, 1939-1945--Campaigns--Soviet Union.
World War, 1939-1945--Causes.
Princeton subject headings:
Germany--History, Military--20th century.
World War, 1939-1945--Campaigns--Soviet Union.
World War, 1939-1945--Causes.