1. Department of Pediatrics Medical University of Warsaw Warsaw Poland
2. Department of Paediatrics, Gastroenterology, Hepatology, Nutrition and Allergology Medical University of Bialystok Bialystok Poland
3. Department of Pediatrics Jagiellonian University Medical College Krakow Poland
4. Department of Pediatrics, Gastroenterology, and Nutrition, Collegium Medicum University of Warmia & Mazury Olsztyn Poland
5. Department of Pneumonology and Allergology for Children Medical University of Warsaw Warsaw Poland
6. City Clinic Warsaw Poland