http://www.tokyo-np.co.jp/article/national/list/201802/CK2018020202000263.html
https://r.nikkei.com/article/DGXMZO26462430S8A200C1000000?s=1
https://www.nikkansports.com/m/battle/sumo/news/201802020000477_m.html
https://r.nikkei.com/article/DGXMZO26462220S8A200C1MM0000
https://www.mrso.jp/stomach/stomach-gastrocamera-pharyngeal-cancer.html