<https://aizawaworks.com/page-1316/%e6%96%b0%e7%9d%80%e8%a8%98%e4%ba%8b%e7%94%bb%e5%83%8f-2/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://aizawaworks.com/page-1316/%E6%96%B0%E7%9D%80%E8%A8%98%E4%BA%8B%E7%94%BB%E5%83%8F-2/>