1. Medical University of Gdańsk, Poland
2. Gdańsk University, Gdańsk, Poland
3. University of Warmia and Mazury in Olsztyn, Poland
4. Municipal Hospital in Olsztyn, Poland
5. University of Social Sciences and Humanities, Poland
6. Independent Public Specialist Health Care Centre in Lebork, Poland
7. Wojewódzki Szpital Specjalistyczny im. Janusza Korczaka, Słupsk, Poland