Columbia subject headings:
Harvard subject headings:
Africa--Politics and government.
Africans--Migrations
Border security--Africa.
Border security--Europe.
Emigration and immigration
Europe--Politics and government.
Princeton subject headings:
Africa--Politics and government.
Africans--Migrations.
Border security--Africa.
Border security--Europe.
Emigration and immigration.
Europe--Politics and government.
Human geography.
International relations.
Political science.
Political sociology.