The impact of the COVID-19 pandemic on the operation of the Emergency Department at the University Hospital in Opole over 12 months: a retrospective study - Grobelczyk, Agnieszka; Lisowska, Ada; Bokszczanin, Marta; Urantówka, Nina; Chobot, Agata (Pediatria Polska - Polish Journal of Paediatrics, 2025)