http://www.nytimes.com/2015/01/25/opinion/sunday/what-happened-to-the-price-of-oil.html?smprod=nytcore-iphone&smid=nytcore-iphone-share "American shale oil has become the decisive new factor in the world oil market in a way that could not have been imagined five years ago. It has proved to be a truly disruptive technology."

http://www.nytimes.com/2014/10/16/world/europe/fall-in-oil-prices-poses-a-problem-for-russia-iraq-and-others.html?smprod=nytcore-iphone&smid=nytcore-iphone-share&_r=0 From Moscow to Caracas, Riyadh to Baghdad, in Tehran, Algiers, Kuwait City and Lagos, political leaders, finance ministers and central bankers have been scrambling to confront the plunge in prices - roughly 25 percent since a peak in June - driven by increased production in the United States and by projections of sustained cuts in demand in many developed countries, as well as decelerating growth in China.