Columbia subject headings:
Harvard subject headings:
Austria--Politics and government--1789-1900.
Belgium--Politics and government--1830-1914.
Europe--Politics and government--1789-1900.
Germany--Politics and government--1815-1866.
Netherlands--Politics and government--1830-
Prussia (Germany)--Politics and government--1848-1866.
Russia--Politics and government--1801-1917.
Spain--Politics and government--1814-1868.
Princeton subject headings:
Europe--Politics and government--1789-1900.