http://www.businessweek.com/news/2013-05-01/oil-options-surge-as-futures-tumble-on-82-year-high-inventories

http://www.fiercefinanceit.com/story/glitch-may-have-longterm-impact-cboe/2013-05-01

https://theoptionsinsider.com/industry/?p=100014245&qcABC=1

http://online.wsj.com/article/SB10001424127887323798104578455032466082920.html

http://www.bloomberg.com/news/2013-05-01/u-s-stock-options-with-biggest-changes-in-implied-volatility.html?cmpid=yhoo

http://www.optionsclearing.com/about/press/releases/2013/05_01.jsp

http://uk.finance.yahoo.com/news/us-sec-votes-5-0-150354785.html

http://blogs.wsj.com/moneybeat/2013/05/01/investors-spooked-ahead-of-big-data-days-look-to-put-options/

http://www.advancedtrading.com/crossingnetworks/nasdaq-omx-launches-etf-exchange/240153954

http://www.advancedtrading.com/high-frequency/after-the-hash-crash-worrying-about-the/240153902

http://www.thetradenews.com/news/Regions/Americas/CFTC_to_address_systemic_risks,_moots_%E2%80%98guidebook%E2%80%99_on_swaps_data.aspx

http://www.bloomberg.com/news/2013-05-01/intercontinental-exchange-net-income-declines-on-energy-trading.html?cmpid=yhoo