<https://daihikaku.jp/wordpress/2020/07/13/%e4%ba%86%e4%bb%a5%e3%80%80%e5%bf%8c-%e3%81%9d%e3%81%ae%ef%bc%92/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://daihikaku.jp/wordpress/2020/07/13/%E4%BA%86%E4%BB%A5%E3%80%80%E5%BF%8C-%E3%81%9D%E3%81%AE%EF%BC%92/>