- Correspondence to Dr Laura Zwaan, Department of Public and Occupational Health, EMGO Institute, VU University Medical Center, Van der Boechorststraat 7, Amsterdam 1081 BT, The Netherlands;
- Received April 8, 2013
- Revised June 28, 2013
- Accepted July 2, 2013
- First published August 13, 2013.
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.