<https://e-contents1.com/how-to-book/%e9%aa%a8%e7%9b%a4%e3%83%80%e3%82%a4%e3%82%a8%e3%83%83%e3%83%88/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://e-contents1.com/how-to-book/%E9%AA%A8%E7%9B%A4%E3%83%80%E3%82%A4%E3%82%A8%E3%83%83%E3%83%88/>