- https://www.kreftregisteret.no/globalassets/cancer-in-norway/2017/cin-2017.pdf, p. 10
- https://www.kreftregisteret.no/globalassets/cancer-in-norway/2017/cin-2017.pdf, p. 11
- https://www.kreftregisteret.no/globalassets/cancer-in-norway/2017/cin-2017.pdf, p. 76
- https://www.kreftregisteret.no/globalassets/cancer-in-norway/2017/cin-2017.pdf, p. 19
- https://www.news-medical.net/news/20100915/94/Norwegian.aspx