https://www.syu.ac.kr/blog/%ec%9e%ac%eb%b3%91%ec%97%ad%ed%8c%90%ec%a0%95%ea%b2%80%ec%82%ac-%ec%9d%bc%ec%9e%90-%eb%b0%8f-%ec%9e%a5%ec%86%8c-%eb%b3%b8%ec%9d%b8%ec%84%a0%ed%83%9d-%ec%95%88%eb%82%b4-2/2020-%ec%9e%ac%eb%b3%91%ec%97%ad%ed%8c%90%ec%a0%95%ea%b2%80%ec%82%ac-%eb%8c%80%ed%95%99%ea%b5%90-%ed%99%8d%eb%b3%b4%eb%ac%b8001/