http://gigazine.net/news/20170821-mathcha/

https://www.nishinippon.co.jp/nnp/national/article/352236/

https://shiology.net/4844-170801-%E9%87%91%E6%B2%A2%E5%A4%A7%E5%AD%A6%E3%83%AD%E3%83%BC%E3%82%B9%E3%82%AF%E3%83%BC%E3%83%AB-%E6%B0%91%E6%B3%951-%E6%9C%9F%E6%9C%AB%E8%A9%A6%E9%A8%93%E3%81%AE%E5%8F%82%E8%80%83%E8%A7%A3%E7%AD%94%E4%BE%8B-e53d…

http://www.nikkei.com/article/DGKKZO20126880Y7A810C1TCJ000/

http://kounomaki.blog84.fc2.com/blog-entry-1037.html