https://www.syu.ac.kr/blog/%ec%9d%98%eb%a3%8c%ea%b8%b0%ea%b8%b0-%ea%b7%9c%ec%a0%9c%ea%b3%bc%ed%95%99ra-%ec%a0%84%eb%ac%b8%ea%b0%80-%ec%a4%91%ea%b8%b0%ea%b3%bc%ec%a0%95-%ec%95%88%eb%82%b4_%ed%95%9c%ea%b5%ad%ec%9d%98%eb%a3%8c/%eb%b6%99%ec%9e%841-%ec%9d%98%eb%a3%8c%ea%b8%b0%ea%b8%b0-%ea%b7%9c%ec%a0%9c%ea%b3%bc%ed%95%99ra%ec%a0%84%eb%ac%b8%ea%b0%80-%ec%a4%91%ea%b8%b0%ea%b3%bc%ec%a0%95_%ec%95%88%eb%82%b4-pdf_page_2/