<https://eepuirst.pixnet.net/blog/post/219301941-%e5%a5%bd%e5%ba%b7%e6%8e%a8%e8%96%a6%e5%bf%83%e5%be%97%7e%e6%98%93%e6%99%b0%e7%be%8e%e5%a6%8d-%e6%88%80%e6%88%80%e7%89%9b%e6%a8%9f%e8%b3%a6%e6%b4%bb%e8%aa%bf%e6%95%b4%e5%8c%96>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://eepuirst.pixnet.net/blog/post/219301941>