1. Lublin University of Technology, Faculty of Mechanical Engineering, Department of Materials Engineering; 36 Nadbystrzycka St. 20-618 Lublin Poland
2. Prof. Stanislaw Popowski Voivoid Children Hospital, Department of Head and Neck Surgery- Maxillofacial Surgery, Otolaryngology and Ophtalmology; ul. Żołnierska 18 A 10-561 Olsztyn PL