Organization of the petroleum exporting countries, MacNeill, M., Plakolm, E., Golpashin, D., & Hammer, W. (2013). Organization of the petroleum exporting countries: Annual report 2012. Organization of the petroleum exporting countries.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रOrganization of the petroleum exporting countries, Maureen MacNeill, Elfi Plakolm, Diana Golpashin, और Wolfgang Hammer. Organization of the Petroleum Exporting Countries: Annual Report 2012. Vienna: Organization of the petroleum exporting countries, 2013.
एमएलए (9वां संस्करण) प्रशस्ति पत्रOrganization of the petroleum exporting countries, et al. Organization of the Petroleum Exporting Countries: Annual Report 2012. Organization of the petroleum exporting countries, 2013.
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