1. Regional Specialist Hospital Wroclaw, Research & Development Centre, Wroclaw, Poland, Faculty of Medicine Wroclaw University of Science and Technology, Wroclaw, Poland
2. Regional Specialist Hospital Wroclaw, Research & Development Centre, Wroclaw, Poland
3. Prince Mieszko Medical Academy in Poznan, Poland
4. Departament of Otolaryngology Pomeranian University of Medicine, Szczecin, Poland