1. http://www.bir.org/ferrous-metals/- accessed on 21.10.2010
2. http://www.bir.org/stainless-steel/- accessed on 21.10.2010
3. http://www.bir.org/non-ferrous-metals/- accessed on 21.10.2010
4. http://www.metso.com/corporation/home_eng.nsf/WebWID/WTB-090526-2256F-0D901?OpenDocument - accessed on 21.10.2010
5. http://www.metso.com/recycling/mm_recy.nsf/WebWID/WTB-050615-2256F-984C1/$File/END_GB_121009.pdf - accessed on 21.10.2010