1. Department of Endocrine Surgery; Third Chair of General Surgery, Jagiellonian University Medical College; Kraków Poland
2. Department of Otology and Laryngology; Division of Thyroid and Parathyroid Surgery; Massachusetts Eye and Ear Infirmary; Department of Surgery; Division of Surgical Oncology; Massachusetts General Hospital, Harvard Medical School; Boston Massachusetts U.S.A
3. Department of Head and Neck Surgery; University of Sao Paulo Medical School; Sao Paulo Brazil