<https://www.sanyu-p.com/info/%e3%81%8a%e7%9f%a5%e3%82%89%e3%81%9b/p3281/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.sanyu-p.com/info/%E3%81%8A%E7%9F%A5%E3%82%89%E3%81%9B/p3281/>