Columbia subject headings:
Labor--Germany--History.
Radicalism--Germany--History.
Revolutions.
Social justice.
Working class--Germany--History.
Harvard subject headings:
Labor--Germany--History.
Radicalism--Germany--History.
Revolutions
Social justice
Working class--Germany--History.
Princeton subject headings:
Labor--Germany--History.
Radicalism--Germany--History.
Revolutions.
Social justice.
Working class--Germany--History.