<https://hyogoservice.com/2014/05/15/%e3%83%87%e3%82%a4%e3%82%ba%e3%80%80%e3%83%ab%e3%83%bc%e3%82%af%e3%82%b9-2/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://hyogoservice.com/2014/05/15/%E3%83%87%E3%82%A4%E3%82%BA%E3%80%80%E3%83%AB%E3%83%BC%E3%82%AF%E3%82%B9-2/>