Columbia subject headings:
Harvard subject headings:
Germany (East)--History--21st century--Congresses.
Germany--History--Unification, 1990--Congresses.
Socialism--Germany--History--21st century--Congresses.
Princeton subject headings:
Germany (East)--History--21st century.
Germany--History--Unification, 1990.
Socialism--Germany--21st century.