Lund Eiliv, Dumeaux Vanessa, Braaten Tonje, Hjartåker Anette, Engeset Dagrun, Skeie Guri, Kumle Merethe
Institute of Community Medicine, University of Tromsø, 9037 Tromsø, Norway.
Int J Epidemiol. 2008 Feb;37(1):36-41. doi: 10.1093/ije/dym137. Epub 2007 Jul 20.