<https://www.sapjp.com/blog/archives/tag/%E3%82%AA%E3%83%B3%E3%82%B3%E3%83%A9%E3%82%A4%E3%82%B6%E3%83%BC/#collectionpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.sapjp.com/blog/archives/tag/%E3%82%AA%E3%83%B3%E3%82%B3%E3%83%A9%E3%82%A4%E3%82%B6%E3%83%BC>