1. Clinical Hospital No 1; Zabrze
2. Silesian University of Technology; Gliwice
3. Medical University of Gdansk; Gdansk
4. Medical University of Silesia; Katowice
5. Medical University of Białystok; Białystok
6. Provincial Children's Hospital; Bydgoszcz
7. Medical University of Łódź; Łódź Poland