<https://manabi-forever.com/2019/03/24/%e8%aa%ad%e8%a7%a3%e3%81%ab%e5%bf%85%e8%a6%81%e3%81%aa%e6%8e%a5%e7%b6%9a%e8%a9%9e/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://manabi-forever.com/2019/03/24/%E8%AA%AD%E8%A7%A3%E3%81%AB%E5%BF%85%E8%A6%81%E3%81%AA%E6%8E%A5%E7%B6%9A%E8%A9%9E/>