<https://jyo-hou.net/2022/04/24/%e4%bf%9d%e8%82%b2%e6%89%80%e5%8d%92%e5%9c%92/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://jyo-hou.net/2022/04/24/%E4%BF%9D%E8%82%B2%E6%89%80%E5%8D%92%E5%9C%92/>