<https://it-afi.com/xserver/xserver-%e3%81%a7-%e7%84%a1%e5%8a%b9%e3%81%aaurl%e3%81%a7%e3%81%99/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://it-afi.com/xserver/xserver-%E3%81%A7-%E7%84%A1%E5%8A%B9%E3%81%AAurl%E3%81%A7%E3%81%99/>