https://www.nhk.or.jp/politics/articles/feature/12514.html

http://youngblood.cocolog-nifty.com/youngblood/2018/12/post-2a7b.html

https://ameblo.jp/ichikawa42/entry-12429239423.html

https://www.yomiuri.co.jp/national/20181229-OYT1T50041.html

https://humitsuki.exblog.jp/29057941/