<https://ishin.org/publishing/%e8%91%97%e6%9b%b8%e5%87%ba%e7%89%88%e3%81%ae%e3%81%8a%e8%aa%98%e3%81%84/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://ishin.org/publishing/%E8%91%97%E6%9B%B8%E5%87%BA%E7%89%88%E3%81%AE%E3%81%8A%E8%AA%98%E3%81%84/>