1. Jakob Vogt, The Portuguese Rule on the Gold Coast, 1469–1682 ( Athens: University of Georgia Press, 1979 ).
2. Paul Lovejoy, Transformations in Slavery ( Cambridge: Cambridge University Press, 2000 ), p. 37.
3. Ralph Austen, “The Trans-Saharan Slave Trade: A Tentative Census,” in Jan S. Hogendorn (ed.), The Uncommon Market: Essays in the Economic History of the Atlantic Slave Trade (New York: Academic Press, 1979), Table 2.8: p. 66.
4. Ralph Austen, “The Nineteenth Century Islamic Slave Trade from East Africa (Swahili and Red Sea Coasts): A Tentative Census,” Slavery and Abolition , 9 (1988): 21–44.
5. Ralph Austin, “The Nineteenth century Islamic Slave Trade from East Africa (Swahili and Red Sea Coasts): A Tentative Census,” in William Gervase Clarence-Smith (ed.), The Economics of the Indian Ocean Slave Trade ( London: Frank Cass 1989 ), pp. 21–44.