Columbia subject headings:
Eavesdropping--Germany (West)
Electronic surveillance--Germany (West)
Espionage--Germany (West)
Intelligence service--Germany (West)
Privacy, Right of--Germany (West)
Wiretapping--Germany (West)
Harvard subject headings:
Telecommunication--Germany--History--20th century.
Telecommunication--Traffic
Wiretapping--Germany--History--20th century.
Princeton subject headings:
Eavesdropping--Germany (West).
Electronic surveillance--Germany (West).
Espionage--Germany (West).
Intelligence service--Germany (West).
Privacy, Right of--Germany (West)
Wiretapping--Germany (West).