<https://ichiru.net/blog/8%e5%9b%9e%e7%9b%ae%e3%81%ae%e6%8e%88%e6%a5%ad%e9%a2%a8%e6%99%af%e3%80%82/#authorImage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://ichiru.net/blog/8%E5%9B%9E%E7%9B%AE%E3%81%AE%E6%8E%88%E6%A5%AD%E9%A2%A8%E6%99%AF%E3%80%82/>