Alpern, Stanley B. “Exotic Plants of Western Africa: Where They Came from and When.” History in Africa 35 (2008): 63–102. http://www.jstor.org/stable/25483718
Possible book/ebook sources - Peanut
The Cambridge World History of Food by Kenneth F. Kiple (Editor); Kriemhild Coneé Ornelas (Editor); Kriemhild Coneè Ornelas (Editor)