<https://igarashi-recycle.com/2019/02/04/%e7%be%8e%e5%93%81-yamaha-%e9%99%a4%e9%9b%aa%e6%a9%9f-yt660/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://igarashi-recycle.com/2019/02/04/%E7%BE%8E%E5%93%81-yamaha-%E9%99%A4%E9%9B%AA%E6%A9%9F-yt660/>