دانلود کتاب اقتصاد Computational Management Science رشته اقتصاد موضوع عمومی فایل pdf زبان انگلیسی چاپ 2016 Oil and gas (O&G) companies’ earnings are substantially affected by the price fluctuations of crude oil, natural gas and refined products, which lead these companies to find ways to minimize their exposure to price risk. The work on investments and selection of efficient portfolios [9], along with the deregulation of energy markets in the United States in the 1980s, exponent ...