<https://gfbeta.co/%e3%82%ac%e3%83%bc%e3%83%ab%e7%b4%b9%e4%bb%8b%e3%81%9d%e3%81%ae3-%e5%8a%a0%e8%b3%80%e7%be%8e%e8%8c%89%e8%8e%89/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://gfbeta.co/tag/2%E5%B9%B4%E7%94%9F/>