Columbia subject headings:
Slave trade--Africa--History--Congresses.
Slave trade--America--History--Congresses.
Slave trade--History--Congresses.
Slavery--Africa--History--Congresses.
Slavery--America--History--Congresses.
Slavery--History--Congresses.
Harvard subject headings:
Slave trade--Historiography--Congresses.
Slave trade--Pictorial works.
Slavery--Historiography--Congresses.
Slavery--Pictorial works.
Princeton subject headings:
Slave trade--Historiography--Congresses.
Slave trade--Pictorial works.
Slavery--Historiography--Congresses.
Slavery--Pictorial works.