<https://petbuddytraining.com/2018/12/15/%e8%b2%93%e8%88%8c%e9%a0%ad%e7%9a%84%e5%a5%a7%e7%a7%98/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://petbuddytraining.com/2018/12/15/%E8%B2%93%E8%88%8C%E9%A0%AD%E7%9A%84%E5%A5%A7%E7%A7%98/>