<https://style.nikkei.com/article/DGXMZO69494930W1A220C2000000?channel=ASH09007>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://style.nikkei.com/article/DGXMZO69494930W1A220C2000000?channel=DF120220194796>