https://skyjournals.org/%eb%b8%94%eb%9e%99%ec%9e%ad%ec%9d%98-%ec%88%a8%ea%b2%a8%ec%a7%84-%ea%b8%b0%ec%88%a0-%ec%b9%b4%eb%93%9c-%ec%b9%b4%ec%9a%b4%ed%8c%85/