<https://www.salon-tria.com/post/\u5B87\u5B99\u306B\u3044\u308B\u3088\u3046\u306A\u6C17\u5206>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.salon-tria.com/post/%E5%AE%87%E5%AE%99%E3%81%AB%E3%81%84%E3%82%8B%E3%82%88%E3%81%86%E3%81%AA%E6%B0%97%E5%88%86>