<https://kidsmirai-blog.com/tag/%e3%82%8f%e3%81%8b%e3%81%8e%e3%82%8a%ef%bc%92%ef%bc%91/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://kidsmirai-blog.com/tag/%E3%82%8F%E3%81%8B%E3%81%8E%E3%82%8A%EF%BC%92%EF%BC%91/>