Authors
Alexandar V. Valkov
ENT Clinic, University Hospital – Pleven
Mario P. Milkov
Department of Dental Medicine, Medical University - Varna
Georgi N. Nikolov
ENT Clinic, University Hospital – Pleven
Boris I. Duhlenski
ENT Clinic, University Hospital – Pleven
Malik Yildiz
ENT Clinic, University Hospital – Pleven