1. Independent Public Healthcare Center of the Ministry of Interior and Administration in Poznań named after Professor Ludwik Bierkowski, Poznań, Poland
2. Voivodeship Polyclinical Hospital in Leszno, Poland
3. Clinical University Hospital in Poznań, Poland
4. Voivodeship Hospital in Poznanań- Wielkopolska Voivodeship Specialization Center, Poznań, Poland