https://purengom.com/2010/07/22/%eb%b2%85%ec%8a%a4-iphone%ec%9a%a9-%ec%95%b1-40-%eb%84%a4%ec%9d%b4%ed%8b%b0%eb%b8%8c-%ec%97%85%ea%b7%b8%eb%a0%88%ec%9d%b4%eb%93%9c/