Columbia subject headings:
Forschungsstelle der Reichspost (Germany)
Germany. Reichsluftfahrtministerium. Forschungsamt.
Intelligence service--Germany--History--Sources.
Secret service--Germany--History--Sources.
World War, 1939-1945--Secret service--Germany--History--Sources.
Harvard subject headings:
Germany--History--1933-1945.
Secret service--Germany--History--20th century.
World War, 1939-1945--Military intelligence--Germany.
World War, 1939-1945--Secret service--Germany.
Princeton subject headings:
Forschungsstelle der Reichspost (Germany)
Germany. Reichsluftfahrtministerium. Forschungsamt
Intelligence service--Germany--History--20th century.
Military intelligence--Germany--History--20th century.