<https://izonsho-blog.com/%e6%96%ad%e9%85%923%e5%b9%b44%e3%83%b6%e6%9c%88%e3%81%8a%e3%82%81%e3%81%a7%e3%81%a8%e3%81%86%ef%bc%81>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://izonsho-blog.com/%E6%96%AD%E9%85%923%E5%B9%B44%E3%83%B6%E6%9C%88%E3%81%8A%E3%82%81%E3%81%A7%E3%81%A8%E3%81%86%EF%BC%81>