http://es.wikipedia.org/wiki/Imperio_songhai
http://es.wikipedia.org/wiki/Tener%C3%A9

Oasis de Bilma (comercian con sal)
https://www.google.es/search?q=oasis+de+bilma&newwindow=1&source=lnms&tbm=isch&sa=X&ei=KJQwU9z-EqjP0AWn8oDoDw&ved=0CAoQ_AUoAg&biw=1366&bih=677#facrc=_&imgdii=_&imgrc=qoFypAvIX5KNfM%253A%3B2bJjtON3p1r_KM%3Bhttp%253A%252F%252Fupload.wikimedia.org%252Fwikipedia%252Fcommons%252F2%252F2a%252FCommerce_transsaharien.jpg%3Bhttp%253A%252F%252Ffr.wikipedia.org%252Fwiki%252FAzala%2525C3%2525AF%3B2214%3B1488