Gravem, Dag F. (21 September 2007). "Metall-avhengighet" (in Norwegian). Oslo: Ny Tid. Archived from the original on 1 September 2009. Retrieved 26 July 2008.
Gravem, Dag F. (21 September 2007). "Metall-avhengighet" (in Norwegian). Oslo: Ny Tid. Archived from the original on 1 September 2009. Retrieved 26 July 2008.