Columbia subject headings:
Africa--History--Chronology.
Black people--History--Chronology.
Slave trade--History--Chronology.
Slavery--History--Chronology.
Harvard subject headings:
Africa--History--Chronology.
Black people--History--Chronology.
Slave trade--History--Chronology.
Slavery--History--Chronology.
Princeton subject headings:
Africa--History--Chronology.
Black people--History--Chronology.
Slave trade--History--Chronology.
Slavery--History--Chronology.