1. http://www.spe.org/spesite/spe/spe/industry/reserves/petroleum_Reserves_Definitions_1997.pdf, Petroleum Reserves Definitions, Petroleum Resources Management System, Society of Petroleum Engineers 1997, Retrieved 2010-10-06.
2. http://www.researchandmarkets.com/research/5787de/heavy_crude_oil_o, Heavy Crude Oil: Outlook to 2020, Report to their offering technologies, Accessed 2011-10-06.
3. http://www.cbi.com/images/uploads/tech_sheets/Visbreaking.pdf, Shell Soaker Visbreaking (2009) Technical Sheet, Retrieved 2011-02-21.
4. SYDEC delayed coking-maximize profit from the bottom of the barrel, Foster Wheeler Brochure 2009, www.fwc.com/publications/pdf/delayedcoking06.pdf, Retrieved 2011-02-21.