Columbia subject headings:
Harvard subject headings:
Education--Germany
Germany
National characteristics, German.
Secret service Germany.
Secret service--Germany
World War, 1914-1918--Causes
World War, 1914-1918--Secret service.
Princeton subject headings:
Education--Germany.
Germany.
National characteristics, German.
Secret service--Germany.
World War, 1914-1918--Causes.
World War, 1914-1918--Secret service.