http://blogs.wsj.com/moneybeat/2015/08/21/fear-flashes-in-options-market-vix-nearly-doubles/

http://www.reuters.com/article/2015/08/21/markets-stocks-options-idUSL1N10W2DB20150821

http://www.chicagotribune.com/news/sns-wp-blm-news-bc-markets21-20150821-story.html

http://www.chicagotribune.com/news/sns-wp-blm-news-bc-markets-global21-20150821-story.html

http://www.bloomberg.com/news/articles/2015-08-24/panic-grips-markets-as-traders-tally-losses-from-global-selloff

http://www.reuters.com/article/2015/08/21/cboe-volume-record-idUSL1N10W2MJ20150821

http://www.bloomberg.com/news/articles/2015-08-23/u-s-stock-index-futures-decline-after-steepest-slump-since-2011

http://www.nytimes.com/2015/08/22/upshot/this-weeks-market-sell-off-may-not-be-such-a-bad-thing.html?_r=0

http://www.bloomberg.com/news/articles/2015-08-21/s-p-500-futures-little-changed-after-stock-rout-erased-2015-gain

http://www.marketwatch.com/story/vix-fear-index-sees-biggest-weekly-jump-ever-2015-08-21

http://blogs.barrons.com/focusonfunds/2015/08/21/some-fear-gauge-the-vix-never-saw-that-one-coming/

http://www.wsj.com/articles/hedge-fund-gains-100-million-in-two-days-on-bearish-china-bet-1440136499