[1] Danish Polyposis Register, Dept. of Surgical Gastroenterology, University of Copenhagen, Hvidovre
[2] Familial Gastrointest. Cancer R., Mount Sinai Hospital, Toronto, Ont.
[3] Italian Polyposis Registry, Milan, c/o A.I. Stom
[4] Familial Polyposis Registry, Cleveland Clinic Foundation, Cleveland, OH
[5] N. Western Region Polyposis Registry, St. Mary's Hospital, Manchester
[6] Polyposis Registry, St. Mark's Hospital, London
[7] Korean Polyposis Registry, Seoul National University Hospital, Seoul
[8] Familial Polyposis Registry, Roswell Park Cancer Institute, Buffalo, NY
[9] Singapore Polyposis Registry, Singapore General Hospital
[10] Dutch Polyposis Registry, University Hospital Leiden, Leiden
[11] Münster Polyposis Registry, University of Münster, Münster
[12] Dept. of Surgical Gastroenterology, Hvidovre Hospital, DK-2650 Hvidovre