http://www.bloomberg.com/news/articles/2015-04-30/u-s-index-futures-signal-stocks-to-extend-drop-as-apple-falls

http://www.minyanville.com/special-features/daily-recap/articles/Nasdaq-AAPL-DowJones-S2526P500-VIX-Nikkei/4/30/2015/id/56040

http://www.bloomberg.com/news/articles/2015-04-30/debt-options-traders-capitulate-on-hedges-for-lower-u-s-rates

http://www.bloomberg.com/news/articles/2015-04-30/spoofing-elephant-in-room-goes-unmentioned-on-cme-earnings-call

http://finance.yahoo.com/news/traders-run-bearish-energy-bets-154206863.html

http://www.reuters.com/article/2015/04/29/highfrequencytrading-lawsuits-idUSL1N0XQ1BZ20150429

http://blogs.wsj.com/moneybeat/2015/04/29/options-volume-slid-in-first-quarter/

http://www.bloomberg.com/news/articles/2015-04-30/india-s-vix-poised-for-monthly-gain-before-april-futures-expire

http://www.wsj.com/articles/cmes-profit-rises-on-higher-trading-volumes-1430392342

http://www.newsweek.com/flash-crash-case-doesnt-add-326066

http://www.marketwatch.com/story/nasdaq-apologizes-for-posting-twitter-earnings-early-2015-04-29?siteid=yhoof2

http://www.reuters.com/article/2015/04/27/markets-credit-idUSL1N0XL14A20150427