<https://it-skill-memo.work/2020/05/16/%e3%80%90c%e3%80%91%e6%96%87%e5%ad%97%e5%88%97%e3%81%ae%e6%95%b0%e5%80%a4%e3%83%81%e3%82%a7%e3%83%83%e3%82%af%e3%82%92%e3%81%99%e3%82%8b/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://it-skill-memo.work/2020/05/16/%E3%80%90c%E3%80%91%E6%96%87%E5%AD%97%E5%88%97%E3%81%AE%E6%95%B0%E5%80%A4%E3%83%81%E3%82%A7%E3%83%83%E3%82%AF%E3%82%92%E3%81%99%E3%82%8B/>