<https://ginza-yamanokai.com/2022/06/04/%e5%a5%a5%e5%a4%9a%e6%91%a9-%e5%9d%8a%e4%b8%bb%e8%b0%b7-%e6%b2%a2%e7%99%bb%e3%82%8a/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://ginza-yamanokai.com/2022/06/04/%E5%A5%A5%E5%A4%9A%E6%91%A9-%E5%9D%8A%E4%B8%BB%E8%B0%B7-%E6%B2%A2%E7%99%BB%E3%82%8A/>