Assessment of selected cytokine levels and vitamin D concentration in children hospitalised due to simple febrile seizures - Grzywna-Rozenek, Ewa; Pomianowska-Kamińska, Kinga; Krakowczyk, Helena; Świętochowska, Elżbieta; Machura, Edyta (Pediatria Polska - Polish Journal of Paediatrics, 2024)