Columbia subject headings:
Harvard subject headings:
Germany (East)--Boundaries--Germany (West)
Germany (West)--Boundaries--Germany (East)
National security--Germany (East)
National security--Germany (West)
Rhön (Germany)--History--20th century.
Princeton subject headings:
Germany (East)--Boundaries--Germany (West)
Germany (West)--Boundaries--Germany (East)
National security--Germany (East)
National security--Germany (West)
Rhön (Germany)--History--20th century.