https://notion.blog/%ed%83%9c%ed%8f%89%eb%ac%b4-2007%eb%85%84-%ea%b8%88%ea%b0%95%ec%82%b0-%ea%b1%b4%eb%b4%89%ec%82%ac-%ec%b6%95%ec%a0%9c%ec%97%90%ec%84%9c/