Columbia subject headings:
Left-wing extremists--Germany.
Political parties--Germany.
Radicalism--Germany.
Societies--History, organization, etc.
Harvard subject headings:
Left-wing extremists--Germany--Congresses.
Political parties--Germany--Congresses.
Radicalism--Germany--Congresses.
Princeton subject headings:
Left-wing extremists--Germany.
Political parties--Germany.
Radicalism--Germany.
Societies--History, organization, etc.