Columbia subject headings:
Germany--Armed Forces--History--20th century.
Military intelligence--Great Britain--History--20th century.
World War, 1939-1945--Causes.
Harvard subject headings:
Germany--Armed Forces--History--20th century.
Military intelligence--Great Britain--History--20th century
World War, 1939-1945--Causes.
Princeton subject headings:
Germany--Armed Forces--History--20th century.
Military intelligence--Great Britain--History--20th century.
World War, 1939-1945--Causes.