<https://tigercsia3.pixnet.net/blog/post/29517906-%e5%89%8d10%e6%9c%88%e5%87%ba%e5%8f%a3%e9%87%91%e9%a1%8d%e5%89%b5%e6%ad%b7%e5%b9%b4%e5%90%8c%e6%9c%9f%e6%96%b0%e9%ab%98%ef%bc%81>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://tigercsia3.pixnet.net/blog/post/29517906>