Vitamin D level in children with chronic kidney disease on conservative treatment – a pilot study - Oleksik, Natalia; Mieleszko, Katarzyna; Prącik, Gabriela; Kleszyk, Magdalena; Adamczyk, Piotr; Dworak, Marta; Machura, Edyta; Szczepańska, Maria (Pediatria Polska - Polish Journal of Paediatrics, 2020)