<https://houkon.jp/housou-hihyou-post/no-57%ef%bc%8f1972%e5%b9%b410%e6%9c%88%e5%8f%b7/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://houkon.jp/housou-hihyou-post/no-57%EF%BC%8F1972%E5%B9%B410%E6%9C%88%E5%8F%B7/>