Columbia subject headings:
Harvard subject headings:
Germany (East). Ministerium für Staatssicherheit--Exhibitions.
Germany (East). Ministerium für Staatssicherheit.
Postal service--Censorship--Germany (East)--Exhibitions.
Postal service--Censorship--Germany (East)--History--20th century.
Wiretapping--Germany (East)--Exhibitions.
Wiretapping--Germany (East)--History--20th century.
Princeton subject headings:
Germany (East). Ministerium für Staatssicherheit
Postal service--Censorship--Germany (East)--History--20th century.
Wiretapping--Germany (East)--History--20th century.