<https://www.syncron.com/#website>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.syncron.com/ja/blog/%E8%B2%A1%E5%8B%99%E4%B8%89%E8%A1%A8%E3%81%8B%E3%82%89%E8%AA%AD%E3%82%80%E3%80%81%E4%BF%9D%E5%AE%88%E9%83%A8%E5%93%81%E3%81%AE%E5%9C%A8%E5%BA%AB%E5%89%8A%E6%B8%9B%E3%81%AE%E3%83%A1%E3%83%AA%E3%83%83/>