Columbia subject headings:
Harvard subject headings:
Berlin (Germany)--History--20th century.
Berlin Wall, Berlin, Germany, 1961-1989
Berlin Wall, Berlin, Germany, 1961-1989--Personal narratives.
Escapes--Germany--Berlin--History--20th century.
Political refugees--Germany--Berlin--History--20th century.
Tunnels--Germany--Berlin--History--20th century.
Princeton subject headings:
Berlin Wall, Berlin, Germany, 1961-1989.
Escapes--Germany (East)--20th century--History.
Escapes--Germany--Berlin--20th century--History.
Mueller family--Biography.
Müller, Rudolf, 1931---Trials, litigation, etc.
Political refugees--Germany (East)--20th century--Personal narratives.
Political refugees--Germany--Berlin--20th century--Personal narratives.
Tunnels--Germany (East)--20th century--History.
Tunnels--Germany--Berlin--20th century--History.