<https://rdd9.com/bbs04/%e6%84%9b%e7%9f%a5%e7%9c%8c/%e6%84%9b%e7%9f%a5%e7%9c%8c%e8%9f%b9%e6%b1%9f%e7%94%ba/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://rdd9.com/bbs04/%E6%84%9B%E7%9F%A5%E7%9C%8C/%E6%84%9B%E7%9F%A5%E7%9C%8C%E8%9F%B9%E6%B1%9F%E7%94%BA/>