<https://a-man-of-40-years-old-blog.com/%e3%82%af%e3%83%ad%e3%83%8d%e3%82%b3%e9%85%8d%e9%81%94%e6%a1%88%e5%86%85%e4%bf%82/#article>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://a-man-of-40-years-old-blog.com/%E3%82%AF%E3%83%AD%E3%83%8D%E3%82%B3%E9%85%8D%E9%81%94%E6%A1%88%E5%86%85%E4%BF%82/>