Columbia subject headings:
Harvard subject headings:
Enemies--History--19th century.
Liberalism--History--19th century.
Political science--History--19th century
Princeton subject headings:
Germany--Politics and government--19th century--Congresses.
Germany--Politics and government--20th century--Congresses.
Liberalism--Germany--History--Congresses.
Political culture--Germany--History--Congresses.