- Correspondence to Silje L Kaspersen, Department of Public Health and General Practice, Norwegian University of Science and Technology, P.O. Box 8905, Trondheim 7491, Norway;
- Received January 17, 2016
- Revised April 12, 2016
- Accepted April 19, 2016
- First published May 10, 2016.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.