1. Department of Surgery, Erasmus University Medical Center, 3000 CA Rotterdam, The Netherlands
2. General and Upper GI Surgery Division, University Hospital of Verona, 37134 Verona, Italy
3. Department of Gastrointestinal Surgery, Ghent University Hospital, B-9000 Ghent, Belgium
4. Department of Thoracic Surgery, University Hospitals Leuven, 3000 Leuven, Belgium