[1] N Estonian Reg Hosp, Surg Clin, EE-13419 Tallinn, Estonia
[2] Med Acad Latvia, P Stradins Clin Univ Hosp, LV-1002 Riga, Latvia
[3] Tartu Univ Clin, Surg Clin, EE-51014 Tartu, Estonia
[4] Valmiera Hosp, Dept Surg, LV-4201 Valmiera, Latvia
[5] Clin Hosp Gailezers, Dept Surg, LV-1038 Riga, Latvia
[6] Wyeth Res, Collegeville, PA USA
[7] Wyeth Res, F-92931 Paris, France