<https://tsukuba-reien.com/2019/06/19/%e5%ae%8c%e7%86%9f%e6%a2%85%e3%81%a8sun%e3%81%a1%e3%82%83%e3%82%93/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://tsukuba-reien.com/2019/06/19/%E5%AE%8C%E7%86%9F%E6%A2%85%E3%81%A8sun%E3%81%A1%E3%82%83%E3%82%93/>