<https://cocosera.info/2020/04/27/%e3%80%90%e9%87%8d%e8%a6%81%e3%81%aa%e3%81%8a%e7%9f%a5%e3%82%89%e3%81%9b%e3%80%91/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://cocosera.info/2020/04/27/%E3%80%90%E9%87%8D%E8%A6%81%E3%81%AA%E3%81%8A%E7%9F%A5%E3%82%89%E3%81%9B%E3%80%91/>