1. Federal State Government-Financed Educational Institution of Higher Education “Volgograd State Medical University” of the MH RF, Volgograd, Russia.
2. Department of Surgery, Federal State Autonomous Institution “National Medical Research Center of Children's Health” of the Ministry of Health of the Russian Federation, Moscow, Russia.
3. RUDN University (Peoples' Friendship University of Russia), Moscow, Russia.
4. Federal State Educational Institution of Additional Professional Education of Russian Medical Academy of Continuing Professional Education, Moscow, Russia.