- Correspondence to: Dr F Ballester Epidemiology and Statistics Unit, Escola Valenciana d’Estudis en Salut-EVES (Valencian School of Health Studies), c/Joan de Garay 21, 46017 Valencia, Spain; ballester_
- Accepted November 11, 2005
- First published March 13, 2006.
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.