<https://rakukatu.com/%e6%a5%bd%e5%a4%a9%e5%b8%82%e5%a0%b4%e3%82%92%e6%a5%bd%e3%81%97%e3%82%80%e3%83%9e%e3%83%9e/1#author>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://rakukatu.com/2676.html>