1. International Iron and Steel Institute World crude steel production, 1950 to 2006.http://www.worldsteel.org/?action=storypages&id=193(accessed November 13, 2007).
2. U.S. Geological Survey. Iron and steel slag. Mineral Commodity Summaries 2007, U.S. Geological Survey.http://minerals.usgs.gov/minerals/pubs/mcs/(accessed November 13, 2007).
3. Ruukki. Raahe Works Environmental report 2006.http://www.ruukki.com/www/corporate.nsf/documents/A73C3FD027FE01F9C22572E4003F560C?openDocument&lang=1(accessed November 13, 2007).