<https://rubytuesdaystore.com/souba/%e3%83%b4%e3%82%a7%e3%82%bc%e3%83%ab%ef%bc%88%e3%83%9b%e3%83%b3%e3%83%80%ef%bc%89%e3%81%ae%e8%bb%8a%e5%a3%b2%e5%8d%b4/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://rubytuesdaystore.com/souba/%E3%83%B4%E3%82%A7%E3%82%BC%E3%83%AB%EF%BC%88%E3%83%9B%E3%83%B3%E3%83%80%EF%BC%89%E3%81%AE%E8%BB%8A%E5%A3%B2%E5%8D%B4/>