Non-nutritive sucking evaluation in preterm newborns and the start of oral feeding: a multicenter study - Neiva, Flávia C. B.; Leone, Cléa R.; Leone, Claudio; Siqueira, Lisiane L.; Uema, Kátia Akiko; Delgado, Susana; Evangelista, Daiana; Rocha, Adriana; Bühler, Karina Bernardis (Clinics, 2014)