1. Pediatric Surgery Students’ Association, School of Medicine, Collegium Medicum, University of Warmia and Mazury in Olsztyn, Poland
2. Department of Surgery, School of Public Health, Collegium Medicum, University of Warmia and Mazury in Olsztyn, Poland
3. Clinical Ward of Paediatric Surgery and Urology, Regional Specialised Children’s Hospital in Olsztyn, Poland