Extraintestinal manifestations in paediatric-onset inflammatory bowel disease depending on disease location and activity - Niewiem, Monika; Buczyńska, Anna; Flak-Wancerz, Anna; Woś, Halina; Kolybacz, Agata; Grzybowska-Chlebowczyk, Urszula (Pediatria Polska - Polish Journal of Paediatrics, 2019)