Columbia subject headings:
Harvard subject headings:
Africa--Emigration and immigration--History--21st century.
Africans--Europe--History--21st century.
Europe--Emigration and immigration--History--21st century.
Human smuggling--Africa--History--21st century.
Human smuggling--Europe--History--21st century.
Human trafficking--Africa--History--21st century.
Human trafficking--Europe--History--21st century.
Slavery--History--21st century.
Princeton subject headings:
Africa--Emigration and immigration.
Europe--Emigration and immigration.
Human smuggling--Africa.
Human smuggling--Europe.
Human trafficking--Africa.
Human trafficking--Europe.