1. American Iron and Steel Institute, 1999a. Significant strides in energy efficiency. http://www.steel.org/facts/power/energy.htm.
2. American Iron and Steel Institute, 1999b. Facts and figures. http://www.steel.org/facts/power/newsteel.htm.
3. American Iron and Steel Institute, Steel Manufacturers Association, and the U.S. Department of Energy, 1999c. The steel industry technology roadmap. http://www.steel.org./mt/roadmap/roadmap.htm
4. Technical efficiency, production functions and conservation supply curves;Blumenstein;Energy Policy,1995
5. Greening, L.D., Greene, D., 1998. Energy Use, Technical Efficiency and the Greenhouse Effect: a Review of the Literature. Hagler Bailly Services, Denver, USA, Final Report, January 1988.