<https://studio-sandk.jp/2017/08/30/%e2%99%aa1%e6%ad%b3%e3%81%ae%e3%83%90%e3%83%bc%e3%82%b9%e3%83%87%e3%83%bc%e2%99%aa/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://studio-sandk.jp/2017/08/30/%E2%99%AA1%E6%AD%B3%E3%81%AE%E3%83%90%E3%83%BC%E3%82%B9%E3%83%87%E3%83%BC%E2%99%AA/>