<https://open2ch-blog.ddns.net/archives/tag/%e4%bb%bb%e5%a4%a9%e5%a0%82switch#breadcrumb>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://open2ch-blog.ddns.net/archives/tag/%E4%BB%BB%E5%A4%A9%E5%A0%82switch>