<https://programming-learning.com/2018/08/13/%e7%b4%a0%e6%95%b0%e5%88%a4%e5%ae%9a-%e9%ab%98%e9%80%9f%e5%8c%96-%e3%82%92%e9%96%a2%e6%95%b0%e3%83%9d%e3%82%a4%e3%83%b3%e3%82%bf%e3%81%a7%e3%82%84%e3%82%8b/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://programming-learning.com/2018/08/13/%E7%B4%A0%E6%95%B0%E5%88%A4%E5%AE%9A-%E9%AB%98%E9%80%9F%E5%8C%96-%E3%82%92%E9%96%A2%E6%95%B0%E3%83%9D%E3%82%A4%E3%83%B3%E3%82%BF%E3%81%A7%E3%82%84%E3%82%8B/>