1. Kingston Hospital, Kingston upon Thames, UK
2. Chirurg Univ Klinik, Heidelberg, FRG
3. Department of General Surgery, U.Z.K.U.L. Leuven, Belgium
4. Department of General Surgery, University Hospital, Rotterdam, The Netherlands
5. Department of General Surgery, Hǒpital Ambroise Paré, Boulogne B, France
6. Department of Surgery, University Hospital, Malmö, Sweden