https://purengom.com/2010/07/01/iphone-%ec%bc%80%ec%9d%b4%ec%8a%a4-%ed%8c%8c%ec%9b%8c%ec%84%9c%ed%8f%ac%ed%8a%b8-%ec%97%90%ec%96%b4%ec%9e%90%ec%bc%93-%ed%81%b4%eb%a6%ac%ec%96%b4/