<https://ub874001.pixnet.net/blog/post/467506367-%e6%a1%83%e5%9c%92%e5%9c%a8%e5%9c%b0%e7%be%8e%e9%a3%9f%e3%80%90%e5%a4%a9%e9%a6%a8%e6%89%8b%e4%bd%9c%e7%94%9c%e6%b9%af%e5%86%b0%e5%93%81%e3%80%91%e5%a4%a9%e7%84%b6%e3%84%9f%e5%b0%9a>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://ub874001.pixnet.net/blog/post/467506367>