<https://walker-a.com/archives/tag/%e8%97%8d%e8%8a%bd%e8%80%b3%e6%a9%9f#breadcrumb>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://walker-a.com/archives/tag/%E8%97%8D%E8%8A%BD%E8%80%B3%E6%A9%9F>