Columbia subject headings:
Harvard subject headings:
Europe--Emigration and immigration--History--Congresses.
Europe--Politics and government--Congresses.
Minorities--Europe--History.
Minorities--Political aspects--Europe--History--Congresses.
Princeton subject headings:
Europe--Emigration and immigration--History.
Europe--Politics and government.
Minorities--Europe--History.
Minorities--Political aspects--Europe--History.