National Research Council (U.S.), Board on Science and Technology for International Development, Lost Crops of Africa: Vegetables, pp. 6, 35f. BooksArchived 20 March 2015 at the Wayback Machine
National Research Council (U.S.), Board on Science and Technology for International Development, Lost Crops of Africa: Vegetables, pp. 6, 35f. BooksArchived 20 March 2015 at the Wayback Machine
"ECHO". Archived from the original on 10 May 2010. Retrieved 6 May 2019.