http://seekingalpha.com/article/3966700-chicago-board-options-exchange-recession-proof-company

http://marketsmedia.com/bats-ipo-boosts-exchange-competition/

http://www.cboeoptionshub.com/2016/04/20/continued-use-listed-options-permitted-final-dol-fiduciary-rules/

http://blogs.wsj.com/moneybeat/2016/04/20/where-has-all-the-volatility-gone-vix-hits-lowest-level-of-2016-2/

http://www.bloomberg.com/news/articles/2016-04-20/brexit-vote-would-be-a-risky-bet-for-u-k-s-future-u-s-says

http://www.insidefutures.com/article/1700983/Low%20Volatility%20in%20Equity%20Markets%20to%20Continue.html

http://blog.markettaker.com/2016/04/19/long-calls-and-bull-call-spreads-4/

http://www.foxbusiness.com/markets/2016/04/19/nyse-byrds-take-flight-on-april-21.html

http://www.nasdaq.com/article/as-silver-etfs-soar-options-activity-turns-brisk-cm608651

http://www.financemagnates.com/binary-options/products-2/breaking-ice-launches-binary-options-nyse-amex-platform/

http://www.bloomberg.com/news/articles/2016-04-20/euro-dollar-volatility-tumbles-ahead-of-brexit-vote-analysis

http://www.forbes.com/sites/fredoltarsh/2016/04/19/stock-market-rallies-to-close-at-year-high-but-options-prices-in-the-sp-indicate-investors-are-wary/#446e270f78c0