<https://blog.betterhelpgroup.com/tag/%e5%ae%b3%e6%80%95%e4%b8%bb%e7%ae%a1/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://blog.betterhelpgroup.com/tag/%E5%AE%B3%E6%80%95%E4%B8%BB%E7%AE%A1/>