<https://exciting-sancha.com/article/%e3%82%ad%e3%83%83%e3%82%ba%e3%82%b9%e3%82%bf%e3%83%bc%e3%82%bf%e3%83%bc%e3%82%bb%e3%83%83%e3%83%88%e4%ba%88%e7%b4%84/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://exciting-sancha.com/article/%E3%82%AD%E3%83%83%E3%82%BA%E3%82%B9%E3%82%BF%E3%83%BC%E3%82%BF%E3%83%BC%E3%82%BB%E3%83%83%E3%83%88%E4%BA%88%E7%B4%84/>