<https://earthstone-connection.com/%e3%80%8a%e4%bb%8f-2-%e2%91%a3%e3%80%8b%e3%81%8a%e4%bb%8f%e5%a3%87/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://earthstone-connection.com/%E3%80%8A%E4%BB%8F-2-%E2%91%A3%E3%80%8B%E3%81%8A%E4%BB%8F%E5%A3%87/>