- M J López, Evaluation and Intervention Methods Unit, Public Health Agency of Barcelona, Spain;
- Received 19 December 2006
- Accepted 6 July 2007
- Published online 29 November 2007.
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.