<https://yaunya.pixnet.net/blog/post/2748051-%e6%9c%80%e8%bf%91%e5%bf%83%e6%83%85%e5%be%88%e4%b8%8d%e5%a5%bd>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://yaunya.pixnet.net/blog/post/2748051>