http://news.sina.com.cn/c/nd/2017-07-20/doc-ifyihrmf2817814.shtml
https://www.inside.com.tw/2017/04/16/the-gray-rhino
https://www.nytimes.com/2017/07/23/business/china-economy-gray-rhinos.html
The Gray Rhino: How to Recognize and Act on the Obvious
Dangers We Ignore, by Michele Wucker, St. Martin's
Press, 2016