<https://g-rinblog.com/cropped-%e5%8d%92%e6%a5%ad%e7%94%9f%e3%82%a2%e3%82%a4%e3%82%b3%e3%83%b3-png/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://g-rinblog.com/cropped-%E5%8D%92%E6%A5%AD%E7%94%9F%E3%82%A2%E3%82%A4%E3%82%B3%E3%83%B3-png/>