<https://www.allurekorea.com/2017/05/23/%ec%a6%90%ea%b1%b0%ec%9a%b4-%ec%85%80%eb%b9%84%ec%9d%98-%ec%a7%91/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.allurekorea.com/2017/05/23/%EC%A6%90%EA%B1%B0%EC%9A%B4-%EC%85%80%EB%B9%84%EC%9D%98-%EC%A7%91/>