Columbia subject headings:
Europe--Foreign relations.
Europe--Politics and government--1815-1871.
Europe--Politics and government--1871-1918.
Harvard subject headings:
Europe--Foreign relations--1815-1871.
Europe--Foreign relations.
Europe--Politics and government--1815-1871.
Europe--Politics and government--1871-1918.
Princeton subject headings:
Europe--Foreign relations.
Europe--Politics and government--1815-1871.
Europe--Politics and government--1871-1918.