1. BP Statistical Review of World Energy, June 2011. www.bp.com/statisticalreview.
2. BP Energy Outlook 2030, January 2011. http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2011/STAGING/local_assets/pdf/2030_energy_outlook_booklet.pdf.
3. Time for Europe to face oil and gas supply realities;Weijermars;First Break,2011
4. Annual Energy Review 2009. Projections: National Energy Modeling System, run REF2011.D120810C,2009
5. Total reserves data RNGR11NUS_1a,2011