Columbia subject headings:
Harvard subject headings:
Bunkers (Fortification)--Germany (East)
Cold War.
Communications, Military.
Germany (East)--Defenses.
Germany (East)--History, Military
Germany (East)--Strategic aspects.
Germany (East). Nationale Volksarmee--History.
National security--Germany (East)
National security--Germany (East)--History
Princeton subject headings:
Bunkers (Fortification)--Germany (East).
Cold War.
Communications, Military--Germany (East).
Germany (East)--Defenses.
Germany (East)--Strategic aspects.
National security--Germany (East)