1. Chest Service, CHU St-Pierre, Bruxelles, Belgium
2. Pneumologie, Ziekenhuis Henri Serruys AV, Oostende, Belgium
3. Novartis Horsham Research Centre, Horsham, RH12 5AB, UK
4. Biostatistics, Novartis Pharmaceuticals Corporation, East Hanover, NJ 07936-1080, USA