http://gigazine.net/news/20170204-future-economic-crisis/

http://karapaia.com/archives/52211851.html

https://ja.wikipedia.org/wiki/%E3%81%8A%E3%82%82%E3%81%AA%E8%BF%91%E4%BB%A3%E8%A5%BF%E6%B4%8B%E7%B5%B5%E7%94%BB%E4%B8%80%E8%A6%A7

http://www.joho-translation.com/topics/column01.html

http://www.nikkei.com/article/DGXBZO49854790R21C12A2000000/

https://www.youtube.com/watch?v=bA4nhk1ifs4

http://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q134734403

http://www.hotaka.jp/kioku/content/view/20/43/

https://www.youtube.com/watch?v=JvgpRdcQLsw

https://ja.wikipedia.org/wiki/%E7%B5%8C%E5%96%B6%E7%AE%A1%E7%90%86%E8%AB%96

https://m.youtube.com/watch?v=B6BNLtOic-4 https://www.youtube.com/watch?v=tt-bEZxHTRI&app=desktop

http://culture.cc.hirosaki-u.ac.jp/english/utsumi/linguistics/lingusitics_ja.html