<https://amberwang0224.pixnet.net/blog/post/320292606-%e9%81%8a%e3%80%82%e5%8f%b0%e4%b8%ad%e5%b0%8f%e6%97%a5%e5%ad%90>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://amberwang0224.pixnet.net/blog/post/320292606>