Columbia subject headings:
Harvard subject headings:
Berlin Wall, Berlin, Germany, 1961-1989
Germany (East)--Boundaries--Germany (West)
Germany (East). Grenztruppen der DDR--History.
Germany (East). Nationale Volksarmee. Kommando Grenze.
Germany (West)--Boundaries--Germany (East)
Military architecture--Germany--Berlin.
Princeton subject headings:
Germany (East). Nationale Volksarmee. Kommando Grenze
Military architecture--Germany--Berlin.