Columbia subject headings:
Germany--Politics and government--1888-1918.
Socialism--Germany--History--19th century.
Socialism--Germany--History.
Sozialdemokratische Partei Deutschlands--History--Sources.
Sozialdemokratische Partei Deutschlands--History.
Working class--Political activity--Germany--History--19th century.
Working class--Political activity--Germany--History.
Harvard subject headings:
Socialism--Germany
Socialism--Germany--History
Sozialdemokratische Partei Deutschlands--History.
Princeton subject headings:
Socialism--Germany--History.
Sozialdemokratische Partei Deutschlands--History.