<https://blog.bisenn.jp/%e6%97%a5%e5%b8%b8%e3%83%96%e3%83%ad%e3%82%b0/%e8%a6%8b%e7%a9%8d%e3%82%82%e3%82%8a%e4%bd%9c%e6%88%90%f0%9f%93%9a/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://blog.bisenn.jp/%E6%97%A5%E5%B8%B8%E3%83%96%E3%83%AD%E3%82%B0/%E8%A6%8B%E7%A9%8D%E3%82%82%E3%82%8A%E4%BD%9C%E6%88%90%F0%9F%93%9A/>