Combined multi-channel intraluminal impedance measurement and pHmetry in the detection of gastroesophageal reflux disease in children with cystic fibrosis Emília da Silva Gonçalves; José Dirceu Ribeiro; Fernando Augusto Lima Marson; Ciro Garcia Montes; Antônio Fernando Ribeiro; Jochen Georg Mainz; Adyléia Aparecida Dalbo Contrera Toro; Juliana Helena Zamariola; Daniela Souza Paiva Borgli; Elizete Aparecida Lomazi; Maria de Fátima Corrêa Pimenta Servidoni;