Columbia subject headings:
Harvard subject headings:
Civil rights and socialism--Germany (East)
Political persecution--Germany (East)
Political persecution--Germany--Potsdam--History--20th century.
Political prisoners--Germany (East)
Political prisoners--Germany--Potsdam--History--20th century.
Prisons--Germany--Potsdam--History--20th century.
Princeton subject headings:
Memorials--Germany (East).
Political prisoners--Germany (East)
Prisons--Germany (East).