Mikkelsen Ellen M, Hatch Elizabeth E, Wise Lauren A, Rothman Kenneth J, Riis Anders, Sørensen Henrik Toft
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Int J Epidemiol. 2009 Aug;38(4):938-43. doi: 10.1093/ije/dyn191. Epub 2008 Sep 9.