Columbia subject headings:
Harvard subject headings:
Business intelligence--Germany (East)--History--20th century.
Business intelligence--Germany (East)--History.
Espionage--Germany (East)--History--20th century.
Espionage--Germany (East)--History.
Germany (East)--Politics and government.
Germany (East)--Relations--Germany (West)
Germany (West)--Relations--Germany (East)
Institut für Wirtschaftswissenschaftliche Forschung--History.
Princeton subject headings:
Business intelligence--Germany (East)--History.
Espionage--Germany (East)--History.
Germany (East)--Politics and government.
Germany (East)--Relations--Germany (West)
Germany (West)--Relations--Germany (East)
Institut für Wirtschaftswissenschaftliche Forschung--History.