Tài liệu tham khảo WikiPedia: Beppu_Ayumi http://ayumi-beppu.yellow-cab.co.jp/blog.html http://www.yellow-cab.co.jp/profile.php?id=5 https://archive.is/20130112002146/ameblo.jp/ayumib... https://web.archive.org/web/20080704091005/http://...
