<https://raityoublog.com/%e8%8d%89%e5%88%88%e3%82%8a%e3%80%80%e5%88%88%e3%82%8a%e6%89%95%e3%81%84%e6%a9%9f/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://raityoublog.com/%E8%8D%89%E5%88%88%E3%82%8A%E3%80%80%E5%88%88%E3%82%8A%E6%89%95%E3%81%84%E6%A9%9F/>