<https://lyes.tw/blog/post/31848125-%e6%9a%ae%e9%a6%99%e7%82%ad%e7%83%a4%e5%90%90%e5%8f%b8>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://lyes.tw/blog/post/31848125-%E6%9A%AE%E9%A6%99%E7%82%AD%E7%83%A4%E5%90%90%E5%8F%B8>