Columbia subject headings:
Harvard subject headings:
Germany--Politics and government--1918-1933--Congresses.
Labor movement--Germany--History--20th century--Congresses.
Unabhängige Sozialdemokratische Partei Deutschlands--History--Congresses.
Princeton subject headings:
Germany--Politics and government--1918-1933--History--Congresses.
Labor movement--Germany--History--20th century--Congresses.
Unabhängige Sozialdemokratische Partei Deutschlands--History--Congresses.