https://blog.faceutil.com/2020/07/16/%eb%b0%b4%eb%93%9c-%ea%b5%ac%eb%b2%84%ec%a0%84-%e3%85%a1-%ea%b4%91%ea%b3%a0-%eb%9c%a8%ea%b8%b0-%ec%a0%84-%eb%b2%84%ec%a0%84-%e3%85%a1-band-3-8-2-signed-%ec%97%85%eb%8d%b0%ec%9d%b4%ed%8a%b8%eb%b0%a9/