https://qooah.com/2010/12/27/android-market-%e8%a9%a6%e7%94%a8%e6%99%82%e9%96%93%e6%94%b915%e5%88%86%e9%90%98%e7%b5%82%e6%83%b9%e7%94%a8%e5%ae%b6%e9%9d%9e%e8%ad%b0/