<https://jpvoyeur.net/%e3%81%8a%e8%b2%b7%e3%81%84%e7%89%a9%e4%b8%ad%e3%81%ab%e7%8b%99%e3%81%84%e3%81%be%e3%81%99/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://jpvoyeur.net/%E3%81%8A%E8%B2%B7%E3%81%84%E7%89%A9%E4%B8%AD%E3%81%AB%E7%8B%99%E3%81%84%E3%81%BE%E3%81%99/>