Columbia subject headings:
Harvard subject headings:
Border crossing--Germany--Halberstadt--History.
Germany (East)--Relations--Germany (West)
Germany (East). Grenztruppen der DDR--History.
Germany (West)--Relations--Germany (East)
Transportation corridors--Germany (East)--History.
Transportation corridors--Germany (West)--History.
Transportation corridors--Germany--Helmstedt--History.
Princeton subject headings:
Border crossing--Germany--Halberstadt--History.
Germany (East)--Relations--Germany (West)
Germany (East). Grenztruppen der DDR--History.
Germany (West)--Relations--Germany (East)
Transportation corridors--Germany (East)--History.
Transportation corridors--Germany (West)--History.
Transportation corridors--Germany--Helmstedt--History.