Fainardi, Valentina, and Enrico Lombardi. “Lung Function Tests to Monitor Respiratory Disease in Preschool Children”. Acta Bio Medica Atenei Parmensis 89, no. 2 (June 14, 2018): 148-156. Accessed January 19, 2021. https://www.mattioli1885journals.com/index.php/actabiomedica/article/view/7155.