Tài liệu tham khảo WikiPedia: Dosso, Niger http://www.britannica.com/EBchecked/topic/169756/D... http://citypopulation.de/Niger-Cities.html //tools.wmflabs.org/geohack/geohack.php?language=v... https://www.reuters.com/article/latestCrisis/idUSL...