<https://www.avdlog.com/vray-zdepth-%e4%bd%bf%e3%81%84%e6%96%b9%e7%b7%a8/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.avdlog.com/tag/%E3%83%AC%E3%83%B3%E3%83%80%E3%83%BC%E3%82%A8%E3%83%AC%E3%83%A1%E3%83%B3%E3%83%88/>