<https://td3win.com/2016/01/15/%e8%a7%92%e5%ba%a6%e3%82%92%e5%a4%89%e3%81%88%e3%81%a6%e8%80%83%e3%81%88%e3%81%a6%e3%81%bf%e3%82%8b-part-1/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://td3win.com/2016/01/15/%E8%A7%92%E5%BA%A6%E3%82%92%E5%A4%89%E3%81%88%E3%81%A6%E8%80%83%E3%81%88%E3%81%A6%E3%81%BF%E3%82%8B-part-1/>