Columbia subject headings:
Harvard subject headings:
Berlin Wall, Berlin, Germany, 1961-1989--Congresses.
Escapes--Germany (East)--Congresses.
Germany (East)--Emigration and immigration--Congresses.
Germany (East)--Politics and government--Congresses.
Political persecution--Germany (East)--Congresses.
Political refugees--Germany (East)--Congresses.
Princeton subject headings:
Germans--Germany (East)--Congresses.
Human rights--Germany (East)--Congresses.
Political persecution--Germany (East)--Congresses.
Prisoners--Germany (East)--Congresses.