1. University Medical Center Utrecht; Julius Center for Health Sciences and Primary Care; Stratenum 6.131 P.O. Box 85500 Utrecht Netherlands 3508
2. University Medical Center Utrecht; Julius Center for General Practice and Patient Oriented Research; P.O. Box 85060 3508 AB Utrecht Netherlands
3. University of Sunderland; Benedict Building St George's Way Sunderland UK SR2 7BW