<https://roseku2008.pixnet.net/blog/post/32123969-%e9%9b%99%e4%ba%ba%e5%9b%a0%e6%9e%9c%28%e5%ae%89%29>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://roseku2008.pixnet.net/blog/post/32123969>