Columbia subject headings:
Assassination--Germany.
Intelligence officers--Great Britain.
Kidnapping--Netherlands.
World War, 1939-1945--Secret service--Germany.
World War, 1939-1945--Secret service--Great Britain.
Harvard subject headings:
Assassination--Germany.
Intelligence officers--Great Britain.
Kidnapping--Netherlands.
World War, 1939-1945--Secret service--Germany.
World War, 1939-1945--Secret service--Great Britain.
Princeton subject headings:
Intelligence service--Great Britain.
World War, 1939-1945--Netherlands--Venlo.
World War, 1939-1945--Secret service.