1. SUMY STATE UNIVERSITY, SUMY, UKRAINE
2. V. N. KARAZIN KHARKIV NATIONAL UNIVERSITY, KHARKIV, UKRAINE
3. STATE INSTITUTION “INSTITUTE OF OTOLARYNGOLOGY NAMED AFTER PROF. O.S. KOLOMIYCHENKO OF THE NATIONAL ACADEMY OF MEDICAL SCIENCES OF UKRAINE”, KYIV, UKRAINE
4. HARKIV MEDICAL ACADEMY OF POSTGRADUATE EDUCATION, KHARKIV, UKRAINE
5. KHARKIV MEDICAL ACADEMY OF POSTGRADUATE EDUCATION, KHARKIV, UKRAINE