<https://ajisai-sano.com/blog/2018/11/27/%e3%83%a9%e3%83%b3%e3%83%81-4/#breadcrumblist>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://ajisai-sano.com/blog/2018/11/27/%E3%83%A9%E3%83%B3%E3%83%81-4/>