<https://cderty2003.pixnet.net/blog/post/52169842-%e7%95%b6%e5%8d%81%e4%ba%8c%e6%98%9f%e5%ba%a7%e8%a2%ab%e7%8b%97%e5%92%ac>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://cderty2003.pixnet.net/blog/post/52169842>