<https://chobinfo.com/blog/2017/08/28/%e3%80%90%e3%82%ad%e3%83%b3%e3%82%b0%e3%83%80%e3%83%a047%e5%b7%bb%e3%80%91%e3%81%ae%e3%83%ac%e3%83%93%e3%83%a5%e3%83%bc/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://chobinfo.com/blog/2017/08/28/%E3%80%90%E3%82%AD%E3%83%B3%E3%82%B0%E3%83%80%E3%83%A047%E5%B7%BB%E3%80%91%E3%81%AE%E3%83%AC%E3%83%93%E3%83%A5%E3%83%BC/>