<https://www.freedom-design.jp/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.freedom-design.jp/news/%E5%A4%8F%E5%AD%A3%E4%BC%91%E6%A5%AD%E3%81%AE%E3%81%8A%E7%9F%A5%E3%82%89%E3%81%9B/>