1. Centre for Health Protection, National Institute of Public Health and the Environment (R.I.V.M.), Bilthoven, the Netherlands;
2. Medicines Evaluation Board, (M.E.B.) Utrecht, the Netherlands;
3. Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, the Netherlands;
4. Healthcare Inspectorate (I.G.Z.), Utrecht, the Netherlands