<https://carol740106.pixnet.net/blog/post/119911341-%e3%80%90%e7%95%aa%e7%b5%84%e3%80%91190724%e3%80%8ckat-tun%e3%81%ae%e4%b8%96%e7%95%8c%e4%b8%80%e3%82%bf%e3%83%a1%e3%81%ab%e3%81%aa%e3%82%8b%e6%97%85>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://carol740106.pixnet.net/blog/post/119911341>